Network routing system, method, and computer program product

ABSTRACT

A method, system, or computer program product to enhance the performance of multi-hop cellular networks or other wireless networks is provided. A wireless device (e.g., cellular telephone) is able to communicate with a base-station in a cell of the cellular network over a non-cellular interface via another wireless device in the cell through the use of multi-hopping. By enabling wireless devices to communicate with a base station in such a manner, the effective coverage area of the cellular network is expanded and the effective capacity of the cellular network is improved. Distributed routing, device management, adaptive scheduling, and distributed algorithms can be used to enhance the overall performance of multi-hop cellular networks.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/399,168, filed on Jan. 5, 2017, which is a continuation ofU.S. patent application Ser. 14/020,511, filed on Sep. 6, 2013, now U.S.Pat. No. 9,578,591, which is a continuation of PCT applicationPCT/US2012/028571 filed Mar. 9, 2012, which claims the benefit of U.S.provisional patent application 61/451,039 filed Mar. 9, 2011, and is acontinuation-in-part of and claims priority to PCT applicationPCT/US2011/045967, filed Jul. 29, 2011, is a continuation-in-part of andclaims priority to PCT application, PCT/US2011/039180, filed Jun. 3,2011. Each of the parent applications are incorporated by referenceherein in their entirety for all purposes

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to wireless communication networks, andmore particularly to routing signals through wireless networks.

Background

In some wireless communication systems, such as cellular communicationsystems, a geographic area of the network is broken up into sub-areasreferred to as “cells.” Each cell may, for example, be about ten squaremiles in area in a larger area of 50 square miles. Each cell may includea device referred to as “base station,” which, in some systems, has atower for receiving/transmitting and a base connected into a publicswitched telephone network (PSTN).

Areas are often divided into cells in order to use spectrum moreefficiently. Typically, a wireless carrier is allocated a limited numberof frequency channels. The use of the cells, in some applications,facilitates frequency reuse, such that, for instance, different users(e.g., individuals operating cellular handsets or devices that send orreceive data over a wireless network) may communicate with differentbase stations over the same frequency in different cells, therebyre-using spectrum while avoiding or reducing interference. Cell phonesystems are often digital with each cell having several channels forassignment to users. In a large city, there may be hundreds of cells.

Cellular networks often include a mobile telephone switching office(MSC) that, in some systems, controls certain aspects of the operationof some or all of the base stations in a region, control that mayinclude control of the connections to a land-based PSTN. For instance,when a user's wireless device gets an incoming call, the MSC may attemptto locate in which cell the user's wireless device is located. The MSCthen may instruct a base station and other system components to assignsresources for the call to the wireless device. The MSC then communicateswith the user's wireless device over a control channel to inform theuser's wireless device what resources to use. Typically, once the user'swireless device and its respective cell tower are connected, the call ison between the wireless device and tower. Similar mechanisms are used tofacilitate data communication (e.g., packet switched data communication)between the wireless device and the network.

In some cellular communication systems, a wireless device directlycommunicates with the cellular base-station. That is, in some cellularwireless systems, the wireless device communicates with the cellularbase-station via a single-hop, meaning that the signals sent between thewireless device and the base station are not mediated through anintermediary device that receives signals from one and passes them on tothe other.

In some systems, at certain times, there may be a relatively largenumber of users attempting to directly communicate with the base-stationin a cell. Some of these users may be located in areas referred toherein as “marginal-to-inoperative regions,” which are areas where thewireless service is spotty because the signal between the wirelessdevice and the cellular base-station is weak or blocked, usually becauseof hilly terrain, excessive foliage, physical distances, concrete walls,or tall buildings. In another example of a marginal-to-inoperativeregion, some of these users may be located in areas referred to hereinas “cell-edges,” which are areas where the interference from neighboringcells is relatively high.

Furthermore, the signal-quality (e.g., signal-strength, signal-to-noiseratio, signal-to-interference and noise ratio, or channel qualityindicator) in some areas of the cell may not be strong enough to meetthe throughput demand of the user. This is because when everything elseis kept constant, the data rate that can be supported between a wirelessdevice and a cellular base-station depends, in part, on thesignal-strength or signal-quality between the device and thebase-station. In some cellular systems, wireless devices are configuredto transmit at a relatively high power when the device is in an area ofthe cell where the signal strength is low. This may help in supportinghigher data rates between that particular device and that particularbase-station. However, higher-power transmission may consume preciousbattery power of the device and also potentially causes moreinterference in the neighboring cells. Causing more interference in theneighboring cells may further hurt the effective capacity of thecellular system.

Some cellular systems may use adaptive modulation and coding. Tofacilitate communication, these systems often use modulation schemes anda certain amount of error correction coding (which, may tend to reducethe data rate or throughput of the wireless link) when the signalstrength between a wireless device and the cellular base-station isrelatively low. Thus, such systems may achieve a data rate between thedevice and the base-station that depends, in part, on the location ofthe device with respect to the base-station. Moreover, in these systems,if the same amount of spectrum was allocated to two similar wirelessdevices in a cell, where the signal-strength or signal-quality betweenthe base-station and the first device is high and the signal-strength orsignal-quality between the base-station and the second device is low,then the first device would (on average) be able to send/receive moreuseful data to/from the base-station. Thus, devices experiencing lowsignal-strength or signal-quality from the base-station may reduce theeffective capacity of the wireless spectrum.

Therefore, there is a need in the art for expanding the effectivecoverage area and improving the effective capacity of cellularbase-stations and cellular networks.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present inventions, a method, system, or computerprogram product for routing in a wireless network is provided. Themethod, in some instances, includes a first wireless terminal choosingto participate as a router. The method further includes the firstwireless terminal deciding whether it will act as a relay or a sink. Inaddition, the method further includes a second wireless terminalchoosing to send data to the first wireless terminal based on whetherthe first wireless terminal is acting as a relay or a sink. As usedherein, the term “sink” refers to the wireless device in a multi-hopconnection that forms the final connection to the base station (or otherinterface to other networks or end data sources), and the term “relay”refers to intermediate connecting wireless devices in the multi-hopconnection.

In another aspect of the present inventions, a method, system, orcomputer program product for improving the performance of a wirelessnetwork is provided. The method includes a wireless terminal choosing adeterministic schedule for transmitting a first type of data and arandomized schedule for transmitting a second type of data.

In another aspect of the present inventions, a method, system, orcomputer program product for improving the performance of a wirelessnetwork is provided. The method includes a first wireless devicereceiving support from a second wireless device and a third wirelessbase-station.

In another aspect of the present inventions, a method, system, orcomputer program product for routing in a wireless network is provided.The method includes a first wireless terminal choosing to send data to athird wireless terminal via a second wireless terminal based on at leastone of the following factors: signal-strength or signal-quality oftransmissions made by the third wireless terminal and received by thefirst wireless terminal are above a threshold greater than zero; andsignal-strength or signal-quality of transmissions made by the secondwireless terminal and received by the first wireless terminal are abovea threshold greater than zero.

In another aspect of the present inventions, a method, system, orcomputer program product for routing in a wireless network is provided.The method includes a second wireless terminal allowing a first wirelessterminal to send data to a third wireless terminal via the secondwireless terminal based on at least one of the following factors:signal-strength or signal-quality of transmissions made by the thirdwireless terminal and received by the second wireless terminal are abovea threshold greater than zero; and signal-strength or signal-quality oftransmissions made by the first wireless terminal and received by thesecond wireless terminal are above a threshold greater than zero.

In another aspect of the present inventions, a method, system, orcomputer program product for routing in a wireless network is provided.The method includes a third wireless terminal allowing a first wirelessterminal to send data to the third wireless terminal via a secondwireless terminal based on at least one of the following factors:signal-strength or signal-quality of transmissions made by the firstwireless terminal and received by the third wireless terminal are abovea threshold greater than zero; and signal-strength or signal-quality oftransmissions made by the second wireless terminal and received by thethird wireless terminal are above a threshold greater than zero.

In another aspect of the present inventions, a method, system, orcomputer program product for managing vehicular traffic is provided. Themethod includes a first wireless terminal sending a beacon. The methodfurther includes a second wireless terminal receiving the beacon andsending a part of the beacon to a traffic-light controller. In addition,the method further includes the traffic-light controller receiving thepart of the beacon and using it to do at least one of the following:monitor vehicles, regulate vehicles, route vehicles, control vehicles,monitor people, regulate people, route people, control people, andcontrol traffic-lights.

In another aspect of the present inventions, a method, system, orcomputer program product for conserving energy is provided. The methodincludes a first wireless terminal sending a beacon. The method furtherincludes a second wireless terminal receiving the beacon and sending apart of the beacon to an electric appliance controller. In addition, themethod further includes the electric appliance controller receiving thepart of the beacon and using it to do at least one of the following:detect people, monitor people, receive instructions, and controlelectric appliances.

In another aspect of the present inventions, a method, system, orcomputer program product for relaying in a wireless network is provided.The method includes a first wireless terminal calculating a first value.The method further includes the first wireless terminal transmitting adata frame along with the first value to a second wireless terminal. Inaddition, the method further includes the second wireless terminalreceiving the data frame and using the first value to do at least one ofthe following: deciding whether to relay the data frame, choosing nextrecipient of the data frame, scheduling the data frame, routing the dataframe, and calculating a second value to replace the first value.

In another aspect of the present inventions, a method, system, orcomputer program product for enhancing social interaction is provided.The method includes a first wireless terminal transmitting a first data.The method further includes a second wireless terminal receiving thefirst data. In addition, the method further includes the second wirelessterminal determining whether the first data and a second data are amatch. Furthermore, the method further includes the second wirelessterminal requesting communication with the first wireless terminal if amatch exists. Additionally, the method further includes the firstwireless terminal accepting the second wireless terminal's request toestablish communication.

In another aspect of the present inventions, a method, system, orcomputer program product for improving the performance of a wirelessnetwork is provided. The method includes a first wireless terminaltransmitting a first data. The method further includes a second wirelessterminal receiving the first data. In addition, the method furtherincludes the second wireless terminal transmitting a second data.Furthermore, the method further includes the first wireless terminalreceiving the second data. Additionally, the method further includes thefirst wireless terminal constructing a third data based on at least oneof the following: the first data and the second data. Moreover, themethod further includes the first wireless terminal transmitting thethird data to the original source of the first data.

In another aspect of the present inventions, a method, system, orcomputer program product for improving the performance of a wirelessnetwork is provided. The method includes a first wireless terminaltransmitting a first data. In addition, the method further includes asecond wireless terminal transmitting a second data at a first powerlevel while receiving the first data. Furthermore, the method furtherincludes the second wireless terminal mitigating the effects oftransmitting the second data to decode the first data.

The foregoing has outlined rather generally the features and technicaladvantages of one or more aspects of the present inventions in orderthat the detailed description of the present invention that follows maybe better understood. Not all of the embodiments of the presentinventions include all of the features described above or offer all ofthe advantages described above, and additional features and advantagesof the present invention will be described hereinafter, which may formthe subject of the claims of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

A better understanding of the present inventions can be obtained whenthe following detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 is a generalized diagrammatic view of an example of a cell in acellular network where wireless devices in the cell have the ability tocommunicate with the base station via multi-hopping in accordance withan embodiment;

FIG. 2 is a block diagram illustrating an exemplary view of thecircuitry of certain components of a cellular telephone in accordancewith an embodiment of the present invention;

FIG. 3 is a flowchart of an example of a method for expanding thecoverage of a cellular network in accordance with an embodiment of thepresent invention;

FIG. 4 is a flowchart of another example of a method for expanding thecoverage of a cellular network in accordance with an embodiment of thepresent invention;

FIG. 5 is a flowchart of an example of a method for routing in awireless network in accordance with an embodiment of the presentinvention;

FIG. 6 is a diagrammatic view of an example of wireless transmissions bywireless terminals in accordance with an embodiment of the presentinvention;

FIGS. 7A-7D are diagrammatic views of an example of a cell in a cellularnetwork where wireless devices in the cell have the ability to cooperatewith each other and the base station via multi-hopping in accordancewith an embodiment of the present invention;

FIG. 8 is a flowchart of an example of a method for routing in awireless network in accordance with an embodiment of the presentinvention;

FIG. 9 is a flowchart of an example of a method for managing vehiculartraffic and a method for conserving energy in accordance with anembodiment of the present invention;

FIG. 10 is a diagrammatic view of an example of a transportation systemwhere the transportation system has the ability to detect the presenceof vehicles in accordance with an embodiment of the present invention;

FIG. 11 is a flowchart of an example of a method for relaying data in awireless network in accordance with an embodiment of the presentinvention;

FIG. 12 is a flowchart of an example of a method for facilitating socialinteraction in accordance with an embodiment of the present invention;

FIG. 13 is a flowchart of an example of a method for operating awireless network in accordance with an embodiment of the presentinvention;

FIG. 14 is a flowchart of an example of a method for operating awireless network in accordance with an embodiment of the presentinvention;

FIG. 15 is a diagrammatic view of an example of cell-edge userinterference in accordance with an embodiment of the present invention;

FIG. 16 is a diagrammatic view of an example of wireless transmissionsby wireless terminals in accordance with an embodiment of the presentinvention;

FIG. 17 is a diagrammatic view of an example of wireless transmissionsby wireless terminals in accordance with an embodiment of the presentinvention;

FIGS. 18A-18D are diagrammatic views of examples of wireless networktopologies in accordance with an embodiment of the present invention;

FIG. 19 is a diagrammatic view of an example of wireless transmissionsby wireless terminals in accordance with an embodiment of the presentinvention;

FIG. 20 is a diagrammatic view of an example of wireless transmissionsby wireless terminals in accordance with an embodiment of the presentinvention; and

FIG. 21 is a flowchart of a process for communicating across a multi-hopnetwork.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The present invention may take a variety of forms, including, in certainembodiments, a wireless network, a wireless device, an integratedcircuit, firmware, microcode, and software stored in a tangible,machine-readable medium. Certain aspects of some embodiments may be usedfor a variety of purposes, including, for example, for expanding thecoverage and improving the capacity of a wireless network, such as acellular network.

In some embodiments, a wireless device (e.g., cellular telephone) isable to (configured to) communicate with a base station in a cell of thecellular network over a non-cellular interface via another wirelessdevice in the cell through the use of multi-hopping. A wireless devicemay request permission to communicate with the base station over anon-cellular interface via hopping off another wireless device when its(the wireless device requesting permission's) signal strength is below athreshold. Other factors that may affect a device's hopping decisioninclude, but are not limited to, battery life, bandwidth usage, type ofdevice, level of mobility, time of day, subscription fees, user profile,non-cellular signal strength, cellular signal strength, level ofwireless interference seen by non-cellular interface, and level ofwireless interference seen by cellular interface. Alternatively, oradditionally, a wireless device may receive a request to communicatewith the base station over a non-cellular interface via hopping off thewireless device that sent the request when that wireless device hasexcess capacity in its (the request sending wireless device's) bandwidthwith the base station. The wireless devices may communicate with oneanother in the cell using a non-cellular protocol thereby potentiallyreducing the usage of the bandwidth of the cellular network. Byconfiguring wireless devices in the cell of the cellular network tocommunicate with a base station in such a manner via multi-hopping, insome embodiments, the coverage area and the capacity of the cellularnetwork is enhanced, though other embodiments may use the same techniqueor other techniques to other effects. Moreover, in some systems, animprovement may be observed in the allocation and use of the cellularnetwork system resources.

While the following discusses embodiments of the present inventions inconnection with wireless devices in a cellular network, the principlesof the present invention may be applied to other systems, including homeappliances, peer-to-peer networks, multi-hop wireless networks, ad-hocnetworks, and mesh networks, which is not to suggest that thesecategories of networks are mutually exclusive.

In the following description, numerous specific details are set forth toprovide a thorough understanding of certain embodiments. However, itwill be apparent to those skilled in the art that the techniquespresented herein may be practiced without applications of the techniquesbeing limited to such specific details of the described embodiments.

As stated in the Background section, currently, in many existingcellular systems, the cellular device directly communicates with thecellular base-station. That is, in these existing cellular systems, thecellular device communicates with the cellular base-station via asingle-hop. As discussed above, there may be hundreds or thousands ofdevices attempting to directly communicate with the base station in acell. Some of these devices may be located in areas referred to hereinas “marginal-to-inoperative regions,” which are areas where celltelephone service is relatively weak or not available because the signalbetween the cellular phone and the base station is blocked, often byhilly terrain, excessive foliage, physical distance, or tall buildings.Further, the signal strength in some areas of the cell may not be strongenough to meet the throughput demand of the device. Therefore, there isa need in the art for extending the coverage area of the base station toserve those devices that may be located in marginal-to-inoperativeregions as well as to meet throughput demand of devices in areas wherethe signal strength is low, though applications of the presenttechniques are not limited to meeting this need, e.g., otherdesign-tradeoffs are envisioned, such as in embodiments having the samethroughput and capacity as conventional systems, but with lower-errorrates, lower power consumption, or decreased interference with othernetworks or devices.

Principles of the present technique, as discussed herein in connectionwith FIGS. 1-4 and other figures, may be used in certain applications toexpand the coverage area and improve the capacity of the base-station.This is expected to allow the base-station, in some embodiments, toserve those devices that may be located in marginal-to-inoperativeregions. Further, principles of the present technique, as discussedherein in connection with FIGS. 1-4 and other figures, in some systems,are expected to relatively efficiently allocate the system resources ofthe cellular network in order to more effectively meet the throughputdemand of devices in areas where the signal strength is low. FIG. 1 is adiagrammatic view of an example of a cell in a cellular network wherewireless devices in the cell have the ability to communicate with thebase station via multi-hopping. FIG. 2 is a block diagram illustratingan exemplary view of the internal circuitry of components of a cellulartelephone. FIG. 3 is a flowchart of a process that, in some embodiments,may be used for expanding the coverage and improving the capacity of acellular network in the scenario of when a wireless device has lowsignal quality by, in some embodiments, hopping off another wirelessdevice in the cell to communicate with the base station. FIG. 4 is aflowchart for an example of a process that may be used for expanding thecoverage and improving the capacity of a cellular network in thescenario of when a wireless device has excess capacity in its bandwidthwith the base station to allow other wireless devices in the cell to hopoff itself to communicate with the base station. FIGS. 5-14 furtherillustrate embodiments of distributed routing, device management,adaptive scheduling, and distributed algorithms using principles of thepresent inventions.

FIG. 1 is a diagrammatic view of a cell 100 in a wireless cellulartelephone network in accordance with an embodiment of the presentinventions. It is noted that only a single cell 100 in a cellularnetwork is depicted for ease of understanding. The principles of thepresent inventions are not limited to any particular number of cells ina particular cellular telephone network or other form of wirelessnetwork.

Cell 100 in a wireless cellular telephone network may be about tensquare miles in area. Each cell 100 in the illustrated cellulartelephone network may include a base station 101 that has a tower 102for receiving/transmitting with wireless devices 103A-D (e.g., cellularphones, netbooks, personal digital assistants, laptop computers).Wireless devices 103A-D may collectively or individually be referred toas wireless devices 103 or wireless device 103, respectively. The term“wireless device”, as used herein, refers to any communication devicethat has the capability of communicating directly via wirelesstransmission with a wireless network. An example of a wireless device isa “cellular device”, which is a wireless device capable of communicatingdirectly via wireless transmission with a base station of a cellularnetwork. While FIG. 1 depicts four wireless devices 103 in cell 100, isthe techniques described are not to be limited in scope to anyparticular number of wireless devices 103 that may be serviced in cell100. An example of a wireless device and a cellular device being acellular telephone for practicing the principles of the presentinvention is discussed below in connection with FIGS. 2.

In accordance with an embodiment of the present invention, wirelessdevices 103 are configured to communicate with base station 101 over“multiple hops.” “Multi-hopping,” as used herein, refers to the processwhereby a wireless device communicates indirectly with a base station(or other interface to other networks or end data sources) via wirelesstransmission to and from one or more other intermediate wirelessdevices. For example, as illustrated in FIG. 1, wireless device 103B maycommunicate with base station 101 via wireless device 103A. In anotherexample, as illustrated in FIG. 1, wireless device 103C may communicatewith base station 101 via wireless devices 103B, 103A. In this example,the range of communication is extended. In another example, asillustrated in FIG. 1, wireless device 103D may communicate with basestation 101 via wireless device 103A. Hence, by allowing wirelessdevices 103B, 103D to communicate with base station 101 via wirelessdevice 103A, there is, in some embodiments, a relatively efficient usageof the bandwidth of the cellular network compared with systems that donot employ multi-hopping. Some possible advantages of multi-hopping arealso shown in FIG. 7 and FIG. 15. A more detailed description ofmulti-hopping will be discussed further below. In one embodiment,wireless devices 103 may communicate with each other via a non-cellularprotocol, thereby reducing the usage of the bandwidth of the cellularnetwork as discussed in further detail below. In one embodiment, theuser of wireless device 103 communicating with base station 101 viamulti-hopping is charged for the service. And in this embodiment, theuser(s) of the intermediary wireless device(s) 103 are not charged forthe service involving the user of wireless device 103 communicating withbase station 101 via the intermediary wireless device(s) 103.

Referring again to FIG. 1, base station 101 may be connected into thepublic switched telephone network (PSTN) 105 via a mobile telephoneswitching office (MTSO) 104. In some systems, each carrier may have amobile telephone switching office (MTSO) 104 that controls the basestations 101 in the city or region and controls the connections to theland based PSTN 105. Different cellular standards, such as GSM, UMTS,WiMAX, LTE, etc. may use terms like mobile switching center (MSC) for104 and public land mobile network (PLMN) for 105.

As discussed above, the illustrated base station 101 has a tower 102 forreceiving/transmitting with wireless devices 103A-D. That is,communication is achieved between wireless device 103 and tower 102,such as via two-way long-range radio frequency communication. A blockdiagram illustrating an exemplary view of the internal circuitry ofcomponents of an example of a wireless device 103 being a cellulartelephone is provided below in connection with FIG. 2.

FIG. 2 is a block diagram illustrating exemplary circuitry of componentsof wireless device 103 (FIG. 1), device 103 being a cellular telephonein accordance with embodiments of the present invention. While thecomponents of wireless device 103 are illustrated as discrete blocks,software or (i.e., and/or) hardware by which these components areimplemented may be organized differently from the block diagram of FIG.2, e.g., software or hardware of different blocks may be intermingled,combined, or broken up into multiple components. Wireless device 103 mayinclude a signal processor 201 and radio transceivers 202A, 202B coupledto a processor 203 (radio transceivers 202A, 202B coupled to processor203 via cellular and non-cellular interfaces 210, 211, respectively, asdiscussed further below). Further, wireless device 103 may include atangible non-transitory data storage medium 204 coupled to processor203. Additionally, wireless device 103 may include an antenna 205 fortransmitting and receiving radio waves (wireless signals). Radiotransceivers 202A, 202B coupled to antenna 205 may transmit and receiveradio communication. Signal processor 201, in some embodiments, convertsradio signals received from radio transceivers 202A, 202B into audiosignals outputted by a speaker 206 and coverts received audio signalsfrom a microphone 207 into radio signals that are transmitted by radiotransceivers 202A, 202B and antenna 205 combinations. Keypad 208 mayinclude internal electrical sensors behind each key visible from theexterior of wireless device 103. These sensors may trigger a particularresponse when a key is depressed by a user of wireless device 103.

Processor 203, in some embodiments, is a microprocessor that may controloperation of other components of thereof wireless device 103. Forexample, processor 203 may control processes occurring within wirelessdevice 103, including responding to user-inputs and executing programmodules to generate menu items, prompts, etc., that are outputted on adisplay 209.

Storage medium 204, in some embodiments, stores computer executableprograms as individual utilities/modules and maintains a database ofuser-entered (or dynamically created/stored) data.

A wireless interface implements protocols that facilitate wirelesscommunication between two wireless terminals. A terminal could be abase-station or a cellular device; moreover, a base-station may also beconsidered as a wireless device. Thus, this document uses the phrasewireless terminal and wireless device interchangeably. At least onewireless interface resides inside each wireless terminal. A “cellularinterface,” as that term is used herein, is a wireless interface that isconfigured to be directly managed by a cellular network. Thus one ormore cellular base-stations could be controlling the behavior of thecellular interface inside a cellular device. Using its cellularinterface, a cellular device can communicate with a base-stationdirectly over a single-hop. In some embodiments, it may become possibleto communicate over multiple hops by using only the cellular interface.A non-cellular interface is a wireless interface that is configured tooperate without being directly managed by a cellular network. There isone exception to this definition: in a device, if a first infrastructurenetwork is managing a first wireless interface and a secondinfrastructure network is managing a second wireless interface, and thefirst wireless interface facilitates multi-hopping in the secondinfrastructure network, then the first wireless interface can beconsidered as a non-cellular interface from the perspective of thesecond infrastructure network. Although a non-cellular interface maymodify its behavior based on the feedback that it gets from the cellularnetwork in which it is facilitating multi-hop, it is not directlyinstructed to do so by the cellular network. In some embodiments, thenon-cellular interface still has independent control over its behaviorand is capable of routing communications in a decentralized manner.

Additionally, in some embodiments, wireless device 103 includes acellular interface 210 and a non-cellular interface 211 coupled toprocessor 203. Cellular interface 210 is further coupled to radiotransceiver 202A; whereas, non-cellular interface 211 is further coupledto radio transceiver 202B. Some implementations may couple cellularinterface 210 and non-cellular interface 211 to the same radiotransceiver and antenna. Cellular interface 210 and non-cellularinterface 211 include a controller 212, 213. Cellular interface 210refers to an interface for communicating with cellular tower 102.Non-cellular interface 211 refers to an interface, such as but notlimited to, Bluetooth™, WiFi™, FlashLinQ™, for communicating indirectlywith cellular tower 102. Moreover, non-cellular interface 211 mayoperate in unlicensed spectrum bands (e.g. ISM bands), licensed spectrumbands (e.g. GSM 850/900/1800/1900 bands), white-spaces spectrum bands(e.g. portions of the sub-1 GHz band in the United States of America),and lightly-licensed spectrum bands (e.g. 3.65-3.70 GHz band in theUnited States of America). As discussed further below, wireless device103 may communicate with each other using a non-cellular interface.Non-cellular interface 211 and cellular interface 210 may use the samewireless spectrum band or different wireless spectrum bands. Ifnon-cellular interface 211 uses different spectrum, peer-to-peercommunication between wireless devices 103 may not use or affect thebandwidth of the cellular network. In one embodiment, cellular interface210 and non-cellular interface 211 may each be embodied on a separateintegrated circuit. In another embodiment, cellular interface 210 andnon-cellular interface 211 may both be embodied on a single integratedcircuit with controller 212/213 located on a separate integratedcircuit. In another embodiment, cellular interface 210 (withoutcontroller 212) and non-cellular interface 211 (without controller 213)along with a single controller (controllers 212/213 combined into asingle controller) may all be embodied on a single integrated circuit.In another embodiment, cellular interface 210 (without controller 212)and non-cellular interface 211 (without controller 213) may be coupledto processor 203, where processor 203 includes a single controller(controllers 212/213 combined into a single controller). In anotherembodiment, cellular interface 210 (with a part of controller 212) andnon-cellular interface 211 (with a part of controller 213) may becoupled to processor 203, where processor 203 includes a singlecontroller (remaining parts of controllers 212/213 combined into asingle controller).

Furthermore, wireless device 103 includes a memory 214 coupled toprocessor 203, cellular interface 210 and non-cellular interface 211.The memory 214 may store instructions for executing various methoddescribed herein, including an application in accordance with theprinciples of the present invention, such as an application forexpanding the coverage of a cellular network as discussed further belowin association with FIGS. 3 and 4. In some embodiments, code foreffecting this application may reside in memory 214, which, like othermemory discussed herein, may be a tangible machine-readable medium.Controller 212, 213 may be a processor configured to execute theinstructions of the application residing in memory 214. In anotherembodiment, the instructions of the application may reside in a separatememory (not shown) in cellular interface 210/non-cellular interface 211.

Aspects of the present invention may be embodied as a system, method orcomputer program product. Accordingly, aspects of the present inventionmay take the form of an entirely hardware embodiment, an entirelysoftware embodiment (including firmware, resident software, micro-code,etc.) or an embodiment combining software and hardware aspects that mayall generally be referred to herein as a “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may be used.A computer readable storage medium may be, for example, but not limitedto, an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer readable storage medium would include the following: anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or flashmemory), a portable compact disc read-only memory (CD-ROM), an opticalstorage device, a magnetic storage device, or any suitable combinationof the foregoing. In the context of this document, a computer readablestorage medium may be any tangible medium that can contain, or store aprogram for use by or in connection with an instruction executionsystem, apparatus, or device.

Some embodiments may receive instructions from a computer readablesignal medium, which may include a propagated data signal with computerreadable program code embodied therein, for example, in baseband or aspart of a carrier wave. Such a propagated signal may take any of avariety of forms, including, but not limited to, electro-magnetic,optical, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that can communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages.

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of thepresent invention. It will be understood that each block of theflowchart illustrations or block diagrams, and combinations of blocks inthe flowchart illustrations or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a controller or processor, such that the instructions,which execute via the controller or processor, create means forimplementing the function/acts specified in the flowchart or blockdiagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a device to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

As stated above, in certain cellular telephone systems, the celltelephone directly communicates with the cellular base station, therebypotentially resulting in limited coverage and inefficient use of theresources. Certain embodiments may expand the coverage area relative tosingle-hop systems and may do so relatively efficiently using theresources of the cellular network by allowing wireless devices (e.g.,cellular phones, netbooks, personal digital assistants, laptopcomputers) to communicate with a cellular base station via hopping offother wireless devices in the cell. Furthermore, wireless devices maycommunicate with one another via a non-cellular protocol therebyminimizing the usage of the bandwidth of the cellular network. Theseprinciples will be discussed below in connection with two scenariosinvolving wireless devices 103. As shown in FIG. 1, one scenarioinvolves wireless device 103 (e.g., wireless device 103B) having lowsignal strength, thereby causing device 103B to attempt to hop offanother wireless device 103 (e.g., wireless device 103A) in cell 100 tocommunicate with base station 101 as discussed below in connection withFIG. 3. In another scenario, wireless device 103 (e.g., wireless device103A) has excess capacity in its bandwidth with base station 101 toallow other wireless devices 103 (e.g., wireless device 103B) in cell100 to hop off itself to communicate with base station 101 as discussedbelow in connection with FIG. 4.

Referring to FIG. 3, FIG. 3 is a flowchart of a method 300 for expandingthe coverage of a cellular network in accordance with an embodiment ofthe present invention. In particular, as stated above, FIG. 3illustrates a technique for expanding the coverage of the cellularnetwork for the scenario involving wireless device 103 (e.g., wirelessdevice 103B) having low signal strength, thereby causing device 103B toattempt to hop off another wireless device 103 (e.g., wireless device103A) in cell 100 to communicate with base station 101.

Referring to FIG. 3, in conjunction with FIGS. 1-2, in step 301,wireless device 103 (e.g., wireless device 103B, wireless device 103D)determines its signal strength on cellular interface 210 from basestation 101.

In step 302, wireless device 103 (e.g., wireless device 103B, wirelessdevice 103D) determines whether its signal strength exceeds a threshold.For example, wireless device 103 may determine if its signal strength isof sufficient strength to communicate with base station 101. The signalstrength may not be strong enough to meet the throughput demand of theuser of wireless device 103. The signal may not even be available due tothe user of wireless device 103 being located in a“marginal-to-inoperative region.”

If the signal strength exceeds the threshold, then, in step 303,wireless device 103 attempts to directly communicate with base station101 via cellular interface 210.

If, however, the signal strength is less than the threshold (i.e.,signal strength is not strong enough to meet the throughput demand ofthe user of wireless device 103), then, in step 304, wireless device 103(e.g., wireless device 103B, wireless device 103D) transmits a requestto other wireless devices 103 (e.g., wireless device 103A) in thevicinity to indirectly communicate with base station 101 by hopping offanother wireless device 103. “Hopping off a wireless device,” as usedherein, refers to indirectly communicating with base station 101 viathat wireless device 103.

In step 305, wireless device 103 (e.g., wireless device 103A) receivesthe request to hop off itself to communicate with base station 101.

In step 306, wireless device 103 (e.g., wireless device 103A) thatreceives the request determines whether to accept the request. In oneembodiment, wireless device 103 (e.g., wireless device 103A) determineswhether to accept the request based on a variety of factors, such asbattery usage, bandwidth usage (referring to the amount of the bandwidththat is currently being used in its connection), time of day pricing,etc. For example, each of, or a subset of, these factors may be comparedagainst respective threshold values and if a factor exceeds thethreshold, the request may not be accepted and if the threshold is met,the request may be accepted.

If (e.g., if and only if) wireless device 103 (e.g., wireless device103A) that receives the request determines to not accept the request,then (e.g., in response to this condition or in response to thiscondition and others), in step 307, wireless device 103 (e.g., wirelessdevice 103A) transmits a response to wireless device 103 (e.g., wirelessdevice 103B, wireless device 103D) to deny the request.

Alternatively, if wireless device 103 (e.g., wireless device 103A) thatreceives the request determines to accept the request, then, in step308, wireless device 103 (e.g., wireless device 103A) transmits aresponse to wireless device 103 (e.g., wireless device 103B, wirelessdevice 103D) to accept the request.

In step 309, wireless device 103 (e.g., wireless device 103B, wirelessdevice 103D) receives permission to communicate with base station 101over non-cellular interface 211 via wireless device 103 (e.g., wirelessdevice 103A) that accepted the request.

In step 310, wireless device 103 (e.g., wireless device 103B, wirelessdevice 103D) communicates with base station 101 over non-cellularinterface 211 via wireless device 103 (e.g., wireless device 103A) thataccepted the request.

Method 300 may include other and/or additional steps that, for clarity,are not depicted. Further, method 300 may be executed in a differentorder presented and that the order presented in the discussion of FIG. 3is illustrative. Additionally, certain steps in method 300 may beexecuted in a substantially simultaneous manner or may be omitted.

As stated above, an alternative scenario using the principles of thepresent invention involves wireless device 103 (e.g., wireless device103A) having excess capacity in its bandwidth with base station 101 toallow other wireless devices 103 (e.g., wireless device 103B) in cell100 to hop off itself to communicate with base station 101 as discussedbelow in connection with FIG. 4.

Referring to FIG. 4, in conjunction with FIGS. 1-2, in step 401,wireless device 103 (e.g., wireless device 103A) transmits a requestover non-cellular interface 211 to other wireless devices 103 (e.g.,wireless devices 103B, 103D) in the vicinity inviting them to hop onwireless device 103 (e.g., wireless device 103A) to communicate withbase station 101 since wireless device 103 (e.g., wireless device 103A)has excess capacity in its bandwidth with base station 101.

In step 402, wireless devices 103 (e.g., wireless devices 103B, 103D)receive the invitation from wireless device 103 (e.g., wireless device103A) to hop on wireless device 103 (e.g., wireless device 103A) tocommunicate with base station 101.

In step 403, wireless devices 103 (e.g., wireless devices 103B, 103D)determine whether to accept the invitation to hop on wireless device 103(e.g., wireless device 103A) to communicate with base station 101. Inone embodiment, wireless devices 103 (e.g., wireless devices 103B, 103D)determine whether to accept the invitation based on a variety offactors, such as the available bandwidth wireless device 103 (e.g.,wireless device 103A) has to offer. For example, if the availablebandwidth is not sufficient to handle the throughput demand, thenwireless device 103 (e.g., wireless device 103B) would not accept theinvitation. Alternatively, if there is sufficient bandwidth to handlethe throughput demand, then wireless device 103 (e.g., wireless device103B) may accept the invitation.

If wireless device 103 (e.g., wireless device 103B) that receives therequest determines to not accept the invitation, then in step 404 of thepresent embodiment, wireless device 103 (e.g., wireless device 103B)disregards the invitation.

Alternatively, if wireless device 103 (e.g., wireless device 103D) thatreceives the request determines to accept the invitation, then in step405 of the present embodiment, wireless device 103 (e.g., wirelessdevice 103D) transmits a response to wireless device 103 (e.g., wirelessdevice 103A) to accept the request.

In step 406, wireless device 103 (e.g., wireless device 103B) thataccepted the request starts communicating with base station 101 overnon-cellular interface 211 via wireless device 103 (e.g., wirelessdevice 103A) that sent the request.

Method 400 may include other and/or additional steps that, for clarity,are not depicted. Further, method 400, like the other processesdescribed herein, may be executed in a different order presented, and itshould be noted that the order presented in the discussion of FIG. 4 isillustrative rather than limiting. Additionally, certain steps in method400, like the other processes described herein, may be executed in asubstantially simultaneous manner or may be omitted.

In another embodiment of the present invention, a non-cellular interfacemay be used to indirectly communicate with a cellular network. Thus insome embodiments, a wireless device with only a non-cellular interfacecan indirectly communicate with a cellular network using principles ofthe present invention. However, in some systems, only a cellularinterface can directly communicate with a cellular network. Although notnecessary in certain embodiments, some wireless devices may have both acellular interface and a non-cellular interface. The cellular andnon-cellular interfaces in a device may operate in the same wirelessspectrum band or in wireless different spectrum bands. Such a wirelessdevice may communicate directly with a cellular network via its cellularinterface and indirectly with a cellular network via its non-cellularinterface. Therefore, such a wireless device can be configured to selectwhether to communicate directly or indirectly with a cellular networkdepending on its state, situations, and surroundings. In making thisdecision, a device may consider (e.g., determine whether to communicatedirectly or indirectly based on) factors such as quality of nearby sinksand relays, quantity of nearby sinks and relays, battery life, source ofpower, average throughput, bandwidth usage, bandwidth needs, bandwidthavailability, type of device, level of mobility, time of day,subscription fees, user profile, non-cellular signal strength andquality, cellular signal strength and quality, level of wirelessinterference seen by a non-cellular interface, level of wirelessinterference seen by a cellular interface, number of hops to a sink, andsurrounding wireless environment. For example, each of, or a subset of,these factors may be compared against respective threshold values, andif a factor exceeds the threshold, in response, indirect communicationmay be selected, otherwise direct communication may be selected.

While devices are communicating directly with a cellular base-stationvia a cellular interface today, in some systems, devices are notcommunicating with a cellular base-station via a non-cellular interfacetoday in certain networks. Indirect communication with a cellularnetwork via its non-cellular interface requires, in some applications, afirst wireless device to send data for a base-station via itsnon-cellular interface to the non-cellular interface of a secondwireless device. If the second wireless device has a good enough directconnection to the base-station via its cellular interface, the secondwireless device may forward the data that it receives via itsnon-cellular interface from the first wireless device directly to thebase-station via its cellular interface. Otherwise, the second wirelessdevice may relay the data that it receives for the base-station on itsnon-cellular interface from the first wireless device to thenon-cellular interface of a third wireless device.

If the third wireless device has a good enough direct connection to thebase-station via its cellular interface, the third wireless device mayforward the data (originated by the first wireless device) that thethird wireless device receives via its non-cellular interface from thesecond wireless device directly to the base-station via its cellularinterface. Otherwise, the third wireless device may relay the data(originated by the first wireless device) that it (the third wirelessdevice) receives for the base-station on its non-cellular interface fromthe second wireless device to the non-cellular interface of a fourthwireless device. In this way the multi-hop route can be extended to asmany hops depending on the constraints, state, and abilities of eachwireless device that is involved.

In some embodiments, base-stations may collaborate with one another tomanage interference at the edge of the cell. However, such methods maymake base-stations shuffle their resources around to mitigateinterference. Principles of the present invention, in some applications,provide these base-stations with an additional way to manage theinterference. If the base-stations detect that serving a wireless deviceat the edge of the cell may cause an amount of interference above athreshold for other wireless devices near the same edge of the cell, oneof the base-stations may communicate with the cellular interface of theconcerned wireless device and request that wireless device to use itsnon-cellular interface to indirectly communicate with the cellularnetwork. In some embodiments, the cellular network may request (e.g.,transmit a wireless signal to the wireless device encoding a command)the wireless device to choose another route to the cellular network.Thus, with loose help from the base-station, the wireless device may beable to mitigate the interference for other wireless devices locatednear the cell-edge and may also help enhance the performance of thecellular network.

Moreover, in some embodiments, the wireless device may also make thisdecision independently without any, or with limited, assistance from thebase-stations (examples of which are shown in FIG. 15). One such way ofdoing this is to analyze (e.g., by a process executed by the wirelessdevice) the signal strength or signal quality from nearby base-stations.If the signal strengths or signal qualities of the top (strongest) fewbase-stations are nearly the same, the device may predict that excessivecell-edge interference is likely and may try to use its non-cellularinterface to indirectly communicate with a nearby base-station. Otherways of predicting and sensing cell-edge user interference in adistributed manner may use (determine based on) one or more of thefollowing (e.g., one or more of the following or a function of thefollowing exceeding a threshold): signal strengths or signal qualitiesof nearby base-stations, quality of nearby sinks and relays, quantity ofnearby sinks and relays, battery life, source of power, averagethroughput, bandwidth usage, bandwidth needs, bandwidth availability,type of device, level of mobility, time of day, subscription fees, userprofile, non-cellular signal strength and quality, cellular signalstrength and quality, level of wireless interference seen by anon-cellular interface, level of wireless interference seen by acellular interface, number of hops to a sink, surrounding wirelessenvironment, history of throughput through various direct and indirectroutes to the cellular network, and feedback from nearby wirelessdevices. In some embodiments, feedback from nearby wireless devices maybe fed into distributed algorithms and protocols, which in someembodiments may determine routing without global knowledge of the stateof every wireless device in the cell or within a certain range.Moreover, in some systems, such feedback only provide indications to thedevice, and the device may still be able to make an independent hoppingdecision to mitigate cell-edge user interference (e.g., based on theindications and other factors). However, in certain systems, distributedapproaches could also be overly cautious and suffer from false alarms.Thus, loose co-ordination with base-stations may be useful in certainimplementations even when wireless devices use their non-cellularinterfaces to communicate with base-stations; principles of the presentinvention, in certain embodiments, accommodate such co-ordination tofurther enhance the coverage and the capacity of cellular networks.

In some networks, a variety of wireless devices communicate withcellular base-stations, and the number of such devices is expected toincrease in the future. Current and expected future single-hop cellularnetworks may not be adequate to support the increasing demand for bettercoverage and capacity. However, in some of the presently describedembodiments, devices could leverage each other's capabilities to use thecellular system more efficiently in order to satisfy their demands forbetter coverage and capacity. One way for devices to make efficient useof the cellular system resources is to employ multi-hopping when seen asbeneficial. Each device may be able to decide on its own to participatein multi-hopping for inter-device hopping to function properly.

Tight centralized control in a multi-hop cellular network may beexercised, but reduces the performance of individual devices in manysystems. This is because a centralized controller likely will not knoweverything about all wireless devices at all times without incurring atremendous amount of overhead. Overheads themselves consume wirelessspectrum and resources of the cellular system. Thus, tight centralizedcontrol of hopping decisions is expected to adversely affect theperformance of multi-hop cellular systems. However, certain embodimentsof the present invention facilitate a multi-hop cellular system wherethe tight centralized control only extends to the cellular interfaces ofthe devices that are communicating to a cellular base-station via theircellular interfaces. Depending on their state, situations, andsurroundings, the wireless devices themselves may make inter-devicehopping decisions in a decentralized manner. A wireless device mayreceive some assistance from the base-station when making hoppingdecisions, but this is not necessary in all embodiments.

Although the hybrid approach (mix of centralized and distributedcontrol) used in embodiments of the present invention is expected tomake, in some systems, multi-hop cellular networks more scalable andefficient, the overall performance of multi-hop cellular networks can befurther enhanced, it is believed, by using distributed routing, devicemanagement, adaptive scheduling, and other distributed algorithms.Examples of these techniques are described below and can be extended toother kinds of wireless networks, such as single-hop cellular networks,multi-hop cellular networks, peer-to-peer single-hop networks,peer-to-peer multi-hop networks, wireless ad-hoc networks, wireless meshnetworks, etc. Herein, the phrases cellular base-station and cellulartower are used interchangeably.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method may include a first wirelessterminal choosing to (e.g., determining whether to) participate as arouter. The method further includes the first wireless terminal decidingwhether it will act as a relay or a sink. In addition, the methodfurther includes a second wireless terminal choosing to send data to thefirst wireless terminal based on whether the first wireless terminal isacting as a relay or a sink. The first wireless terminal may alsotransmit a first metric describing cellular signal strength and qualityseen by a nearby sink if acting as a relay. The first wireless terminalmay also transmit a second metric describing cellular signal strengthand quality seen by the first wireless terminal if acting as a sink.

The above-described embodiment may allow nearby wireless terminals toroute packets to sinks via relays in a distributed manner. This isbecause, in some systems, each wireless terminal independently decideswhether to act as a relay or a sink based on certain factors. Forexample, the first wireless terminal may choose to participate as arouter based on at least one of the following factors: quality of nearbysinks and relays, quantity of nearby sinks and relays, battery life,source of power, average throughput, bandwidth usage, bandwidth needs,bandwidth availability, type of device, level of mobility, time of day,subscription fees, user profile, non-cellular signal strength andquality, cellular signal strength and quality, level of wirelessinterference seen by a non-cellular interface, level of wirelessinterference seen by a cellular interface, number of hops to a sink, andsurrounding wireless environment. For example, each of, or a subset of,these factors may be compared against respective threshold values and ifa factor exceeds the threshold, the first wireless terminal may act as arouter and if the threshold is not met, the first wireless terminal maynot act as a router.

Moreover, the first wireless terminal may determine whether it will actas a relay or a sink based on at least one of the following factors:quality of nearby sinks and relays, quantity of nearby 1sinks andrelays, battery life, source of power, average throughput, bandwidthusage, bandwidth needs, bandwidth availability, type of device, level ofmobility, time of day, subscription fees, user p1rofile, non-cellularsignal strength and quality, cellular signal strength and quality, levelof wireless interference seen by a non-cellular interface, level ofwireless interference seen by a cellular interface, number of hops to asink, and surrounding wireless environment. For example, each of, or asubset of, these factors may be compared against respective thresholdvalues and if a factor satisfies the threshold, the first wirelessterminal may act as a sink and if the threshold is not met, the firstwireless terminal may act as a relay.

Furthermore, the second wireless terminal may determine whether to senddata to the first wireless terminal based on at least one of thefollowing factors: whether the first wireless terminal is acting as arelay or a sink, quality of nearby sinks and relays, quantity of nearbysinks and relays, battery life, source of power, average throughput,bandwidth usage, bandwidth needs, bandwidth availability, type ofdevice, level of mobility, time of day, subscription fees, user profile,non-cellular signal strength and quality, cellular signal strength andquality, level of wireless interference seen by a non-cellularinterface, level of wireless interference seen by a cellular interface,number of hops to a sink, and surrounding wireless environment. Forexample, each of, or a subset of, these factors may be compared againstrespective threshold values and if a factor satisfies the threshold, thesecond wireless terminal may send data to the first wireless terminaland if the threshold is not met, the second wireless terminal may notsend data to the first wireless terminal.

FIG. 5 is a flowchart of a method for routing data through a wirelessnetwork in accordance with an embodiment of the present invention. Instep 506, a first wireless terminal determines whether to participate asa router based on at least one of the factors mentioned in step 502. Instep 508, the first wireless terminal makes the correspondingdetermination. If the first wireless decides to act as a router, in step512 the first wireless terminal further determines whether it will actas a relay or a sink based on at least one of the factors mentioned instep 502. In step 514, a second wireless terminal determines whether tosend data to the first wireless terminal based on at least one of thefactors mentioned in step 502. In step 516, the second wireless terminalmakes the corresponding determination. If the second wireless terminaldecides to send data to the first wireless terminal, it does so in step520.

In certain embodiments, a sink may be an end-destination or a gateway toan adjoining network. For example, a first wireless device may becommunicating with a second wireless device via its (the first wirelessdevice's) non-cellular interface and communicating with a cellular towervia its (the first wireless device's) cellular interface. If the secondwireless device wants to communicate to the cellular network via thefirst wireless device, the first wireless device is a sink for thesecond wireless device because it acts as a gateway to the cellularnetwork. Another example includes a third wireless device sendingpackets destined for a fourth wireless device in a peer-to-peer setting.In this example, the fourth wireless device is a sink for the thirdwireless device because it is the end destination for the packetsoriginated by the third wireless device. It should be noted that thedefinition of a sink is contextual. It depends on the wireless devicethat originates packets.

In certain embodiments, a relay is an intermediate node in the routefrom a wireless device to a sink. For example, a first wireless devicemay send packets destined for a third wireless device via a secondwireless device. The second wireless device is a relay for the firstwireless device when relaying packets originated by the first wirelessdevice to the third wireless device. There may be one or more relays ina route from an originating device to a sink. It should be noted thatthe definition of a relay is contextual. It depends on the wirelessdevice that originates packets.

In certain embodiments, a wireless device may determine whether to actas a sink or a relay depending on the quality and quantity of nearbysinks and relays. For example, in a location where low cellular signalstrength and quality is experienced by most wireless devices, a wirelessdevice that gets moderate cellular signal strength and quality from thecellular towers may determine whether to act like a sink to help otherwireless devices access the cellular network in a more efficient manner.In a location where moderate cellular signal strength and quality isexperienced by most wireless devices, a wireless device that getsmoderate cellular signal strength and quality from the cellular towersmay decide to act like a relay instead.

In certain embodiments, a wireless device may determine whether to actas a router only when it has enough battery life available or when it isplugged into AC power. A wireless device that has multiple antennas andother circuitry that helps it communicate efficiently with an adjoiningnetwork, such as a cellular network, may determine to be a sink forother less sophisticated nearby devices. A wireless device may determineto act as a router, relay, and/or sink based on whether (e.g., if—i.e.,if or if and only if) it has enough bandwidth available and/or if it cansupport reasonable throughputs for other devices. Other device-basedfactors and environment-based factors could also help wireless devicesdecide whether to act as a router, relay, and/or sink.

A wireless device may, in some systems, choose one relay/sink overanother based on the factors mentioned above. Some of these factorsenhance user experience by taking into account user-based factors suchas bandwidth needs and network-based factors such as average throughput.Using such factors can help the wireless device choose good routes to anadjoining network. For example, a wireless device may determine whetherto communicate indirectly with a cellular tower via multiple-hopsinstead of over a single-hop because the average throughput for themulti-hop route is higher. When the average throughput for the multi-hoproute is lower, the device may revert to using the single-hop connectionto increase the likelihood of a good user experience.

One application of certain embodiments arises in multi-hop cellularnetworks. A relay (or intermediate node) may occasionally transmit ametric describing cellular signal strength and quality seen by a nearbysink. It may also transmit other data descriptive of the desirability ofa potential connection, such as number of hops to a wireless sink andits own device state. Moreover, a sink (gateway node) may occasionallytransmit a metric describing cellular signal strength and quality seenby the sink. It may also transmit other useful data, such as number ofhops to a wireless sink and its own device state. Such information canhelp originating nodes find routes to sinks via relays in a distributedmanner. The metrics may be transmitted via periodic beaconing (e.g. IEEE802.11 access points) or via distributed beaconing (e.g. IEEE 802.11ad-hoc devices).

In another embodiment of the present invention, a method for improvingthe performance of a wireless network is provided. The method mayinclude a wireless terminal choosing a deterministic schedule fortransmitting a first type of data and a randomized schedule fortransmitting a second type of data. The wireless terminal may select adeterministic schedule for transmitting the first type of data and arandomized schedule for transmitting the second type of data, whereinthe choice of schedule may be based on at least one of the followingfactors: schedules of nearby devices, queue-lengths, quality of nearbysinks and relays, quantity of nearby sinks and relays, battery life,source of power, average throughput, bandwidth usage, bandwidth needs,bandwidth availability, type of device, level of mobility, time of day,subscription fees, user profile, non-cellular signal strength andquality, cellular signal strength and quality, level of wirelessinterference seen by a non-cellular interface, level of wirelessinterference seen by a cellular interface, number of hops to a sink, andsurrounding wireless environment.

In the above embodiment, the wireless terminal may select adeterministic schedule for transmitting the first type of data and arandomized schedule for transmitting the second type of data, whereinthe type of data is based on at least one of the following factors:direction, quantity, importance, desired quality-of-service, surroundingwireless environment, network congestion, network condition,queue-lengths, and throughput. For example, each of, or a subset of,these factors may be compared against respective threshold values orcategories and if a factor satisfies the threshold or falls in thecategory, the device may select a deterministic schedule and if thethreshold is not met or the category is not applicable, the device maychoose a random schedule. Direction could be either uplink or downlink.Quantity could be defined in terms of bandwidth utilized, bandwidthneeded, and queue-lengths, depending on the application.Quality-of-service depends on the application being supported. Forexample, delay sensitive applications such as voice could benefit from amore deterministic schedule and file transfers could use a randomizedschedule when not too many deterministic slots are available.Surrounding wireless environment could include the topology, prevalenttraffic patterns, activity factors, schedules, numbers, needs, andcapabilities of nearby nodes. The surrounding wireless environment mayalso include network factors, such as the amount of congestion in thenetwork and the condition of the network in terms of latency, delay, andjitter.

In the above embodiment, the wireless terminal may select adeterministic schedule and a first inter-frame spacing for transmittingthe first type of data. The wireless terminal could also choose arandomized schedule and a second inter-frame spacing for transmittingthe second type of data. Inter-frame spacing is the delay between theprevious frame and the next transmission. The IEEE 802.11n standarddefines examples of inter-frame spacing (IFS) in detail.

In the above embodiment, the wireless terminal may select adeterministic schedule and a first contention window for transmittingthe first type of data. The wireless terminal may select a randomizedschedule and a second contention window for transmitting the second typeof data. Contention window is an interval of numbers from which counterscan be chosen to resolve contentions and collisions between wirelessdevices. The IEEE 802.11n standard describes examples of contentionwindow in detail.

In the above embodiment, the wireless terminal may select adeterministic schedule and a first transmit opportunity for transmittingthe first type of data. The wireless terminal may select a randomizedschedule and a second transmit opportunity for transmitting the secondtype of data. Transmit opportunity is the time for which a wirelessdevice gets to access the wireless channel and transmit frames. Transmitopportunity could also be measured in bits and bytes instead of units oftime. The IEEE 802.11n standard describes examples of transmitopportunity in detail.

FIG. 16 is a generalized diagrammatic view of an example of wirelesstransmissions by wireless terminals in accordance with an embodiment ofthe present invention. In particular the figure shows example schedules.Schedule 1692 is based on a contention resolution mechanism known asexponential randomized back-off (ERB). Timeline 1693 shows theprogression of time. Previous frame 1690 may be a data, control, ormanagement frame. A distributed-IFS (DIFS) 1694 separates the previousframe and the first mini-slot 1696. Each mini-slot is mini-slot-time(MST) long in duration. When a wireless device needs to transmit a frameon the wireless channel, the device of this example selects a random(e.g., a pseudo-random function) counter and counts it down each timeMST elapses. In some embodiments, a wireless device may only count downits counter when the device perceives the wireless channel to beavailable or clear. In contrast to schedule 1692, schedule 1649 isasymmetric and can schedule different data in different ways. Firstmini-slot 1656 is reserved for a first downlink transmitter. Secondmini-slot 1657, in this example, is available for any wireless device touse. Thus, every odd mini-slot of the present example is reserved forone or few transmitters of downlink frames. This is believed to allowfor various transmitters of downlink frames to use a more deterministicschedule. However, in some systems, any wireless device can access thechannel in every even mini-slot. To resolve contentions and collisions,wireless devices could use ERB. This, in certain applications, isbelieved to make wireless devices transmitting in even mini-slots tohave a randomized schedule. Wireless devices could use the evenmini-slots to transmit uplink frames. Instead of differentiating trafficbased on uplink and downlink directions, traffic may be differentiatedbased quantity, importance, desired quality-of-service, surroundingwireless environment, network congestion, network condition,queue-lengths, and throughput. Note that mini-slot 1656 is labeled D1and mini-slot 1672 is labeled D1*. The * indicates that D1* is an extraslot for the downlink transmitter that uses D1. One way to facilitatefairness between transmitters of downlink frames is to require thefollowing. After using mini-slot D1, the first downlink transmitter inthis example must either wait for the current round of downlinktransmissions to finish or use D1*. Since D1* comes after D8, thedownlink transmitter corresponding to D8 is believed to get access tothe wireless channel in a fair manner. Moreover, the overhead of a fewMSTs to ensure this fairness is believed to not hurt the performancemuch. If the first downlink transmitter uses D1*, it may not use D1 inthe next round of downlink transmissions. Thus, the first downlinktransmitter is believed to be fair to other downlink transmitters. Oncean extra downlink slot (marked with a *) is used by a wireless device,other wireless devices can, in this example, assume that the currentround of downlink transmissions is over and the next round is about tobegin. In the next round, wireless devices can use their normal downlinkslots (i.e. slots without a *) to transmit frames. Schedules 1601 and1625 are other asymmetric schedules that can also be used.

FIG. 18 is a generalized diagrammatic view of examples of wirelessnetwork topologies in accordance with an embodiment of the presentinvention. FIG. 18A is an example of a 2-dimensional single-hoptopology. Each cube, such as cube 1812, represents a base-station andthe wireless network surrounding it. If base-stations in adjacent cubesuse the same network resources at the same time, they will interferewith each other due to collisions. To achieve a certain level ofperformance, adjacent base-stations can be orthogonalized in time,frequency, code, space, etc. FIG. 18A shows that 4 orthogonalizationscould provide a certain level of performance and keep thecross-interference between nearby base-stations under an acceptablethreshold limit. Orthogonalizations 1804, 1806, and 1810 are shown usingdifferent patterns to reflect their use of different network resources.FIG. 18B is an example of a 2-dimensional multi-hop topology. Eachparallelepiped, such as parallelepiped 1828, represents a linearmulti-hop network consisting of three or more wireless terminals. Ifwireless terminals in adjacent parallelepiped use the same networkresources at the same time, they may interfere with each other due tocollisions. To achieve a certain level of performance, adjacent wirelessterminals can be orthogonalized in time, frequency, code, space, etc.FIG. 18B shows that 2 orthogonalizations could provide reasonableperformance and keep the cross-interference between nearby wirelessterminals under a reasonable limit. Orthogonalizations 1824 and 1826 areshown using different patterns because they try to use different networkresources. FIG. 18C is a common 3-dimensional single-hop topology anduses 8 different orthogonalizations. FIG. 18D is a common 3-dimensionalmulti-hop topology and uses 4 different orthogonalizations. In wirelessnetworks, spectrum is often limited. Thus, excessive orthogonalizationsare expected to, in some scenarious, hurt the overall capacity andspectral efficiency of the wireless network. However, too feworthogonalizations may lead to excessive interference/collisions and mayhurt overall performance. FIG. 18 represents one way to strike a balanceand is believed to achieve reasonable performance. Asymmetric schedules1601, 1625, and 1649 shown in FIG. 16 have 2, 4, and 8 orthogonaldownlink slots; thus they may be used for the common topologies shown inFIG. 18 to facilitate cooperation and coexistence between wirelessterminals. When downlink slots of asymmetric schedules in FIG. 16 areassigned to segments of the topologies shown in FIG. 18, one may takeinto account the relative positions of the segments and assign downlinkslots accordingly. For example, segments of topologies that will beprone to cell-edge user problems or hidden node problems can beseparated further apart in the asymmetric downlink schedule. This mayallow enough control frames (such as IEEE 802.11 RTS/CTS frames) to beexchanged to mitigate the cell-edge user and hidden node problems.

FIG. 6 is a generalized diagrammatic view of wireless transmissions bywireless terminals in accordance with an embodiment of the presentinvention. Schedules 601, 625, and 649 are some other examples ofasymmetric schedules. These differ from asymmetric schedules shown inFIG. 16 in that they do not rely on extra downlink slots (* marked) tofacilitate fairness. These schedules could be more suitable in certainsituations.

FIG. 17 is a generalized diagrammatic view of wireless transmissions bywireless terminals in accordance with an embodiment of the presentinvention. Schedules 1701, 1725, and 1749 are some other examples ofasymmetric schedules. These may be thought of as a hybrid mix ofschedules shown in FIG. 6 and FIG. 16. These schedules could be moresuitable in certain situations.

FIG. 19 is a generalized diagrammatic view of wireless transmissions bywireless terminals in accordance with an embodiment of the presentinvention. Schedules 1901, 1925, and 1949 are some other examples ofasymmetric schedules. Schedule 1901 shows that downlink and uplinkmini-slots do not have to be interleaved like the downlink and uplinkmini-slots of schedules in FIG. 16. However, to exploit asymmetry intopologies and traffic patterns, downlink and uplink can be decoupled inthe way shown in schedule 1901. Moreover, uplink mini-slots could have alower inter-frame spacing in schedules such as 1925. Lastly, in someembodiments, downlink schedules do not have to be deterministic in orderto get reasonable performance. For instance, in some systems, as long asthey are decoupled, both uplink and downlink transmissions could berandomized as is shown in schedule 1949. Schedules shown in FIG. 19could be more suitable in certain situations.

Using the above examples, wireless terminals may adaptively switch fromone schedule to another schedule depending on topology, number,schedules, needs, activity, and traffic patterns of other nearbywireless terminals. Beacon frames, control frames, management frames,data frames, or other wireless communication signaling may be used toprovide topology, number, schedules, needs, activity, and trafficpatterns of a first wireless terminal to a second wireless terminal.Moreover, wireless terminals may cooperate and coordinate to converge toone or more schedules based on at least one of the following factors:quality of nearby sinks and relays, quantity of nearby sinks and relays,battery life, source of power, average throughput, bandwidth usage,bandwidth needs, bandwidth availability, type of device, level ofmobility, time of day, subscription fees, user profile, non-cellularsignal strength and quality, cellular signal strength and quality, levelof wireless interference seen by a non-cellular interface, level ofwireless interference seen by a cellular interface, number of hops to asink, current state of the second wireless terminal, current state ofthe first wireless terminal, participation policy being used by thesecond wireless terminal, participation policy being used by the firstwireless terminal, and surrounding wireless environment. Request (REQ)frames use a different inter-frame-spacing than other frames. REQ framesmay be used by nearby nodes to get a node to use ERB scheduling or use aless aggressive schedule. A node may crowd-source REQ frames from nearbynodes before taking action. This, in some systems, is expected toincrease robustness, performance, and cooperation. When asymmetricscheduling does not lead to good performance and throughput, wirelessterminals may adaptively fall back to using exponential randomizedback-off scheduling. Depending on their needs and current networkconditions, wireless terminals could adaptively switch to normal,conservative, or aggressive schedules. Schedule 1601 could be consideredmore aggressive than schedule 1649 in FIG. 16 because wireless terminalscould potentially get deterministic slots to transmit more frequently inSchedule 1601. Moreover, higher transmit opportunities (TXOP) may beprovided to nodes that need more bandwidth. In this way, nodes usingdeterministic slots could get different priorities by using differentTXOPs. Wireless terminals employing TXOP often use acyclic-redundancy-check for each fragment even when fragments arecontinuously burst out or are burst out with a separation of reduced-IFS(RIFS). This may improve robustness, especially for higherphysical-layer rates because more bytes are sent through while using thesame number of symbols (or TXOP time). When interfering deterministicflows are allowed to happen in parallel, flows using higherphysical-layer rates can transmit more number of bytes in the sameamount of time than flows using lower physical-layer rates. Thus, moreframe aggregation could be needed for flows using higher physical-layerrates when employing TXOP. Thus, having more frequent CRC checks forflows using higher physical-layer rates could be useful.

The above embodiment may benefit if the first type of data is decoupledfrom the second type of data. For example, wireless networks that areused to access the Internet could have two types of data or traffic:downlink traffic and uplink traffic. Transmitters of downlink trafficmay often be fewer in number than transmitters of uplink traffic. Forexample, one wireless base-station could be serving several wirelessdevices. In this example, the downlink direction is from the wirelessbase-station to the wireless devices and the uplink direction is fromthe wireless devices to the wireless base-station. Although there mayoften be fewer transmitters of downlink traffic, downlink Internettraffic may often be heavier than uplink Internet traffic.

The above embodiment may allow nodes in the wireless network to decouplethe plane of competition between uplink and downlink traffic. As aresult, uplink traffic may compete with other uplink traffic anddownlink traffic may compete with other downlink traffic for access tothe wireless channel. Moreover, the few downlink transmitters may thencoordinate and cooperate with each other to coexist on the same wirelesschannel. Furthermore, adding determinism to scheduling of downlinkframes may reduce contentions and collisions between transmitters ofdownlink frames. Also, determinism may further reduce the penalties andoverheads associated with retransmissions. Lastly, determinism may allowmore downlink flows to happen in parallel, allowing downlinktransmitters to use the available network resources more aggressivelyand efficiently.

Uplink Internet traffic may often be less heavier than downlink Internettraffic. Moreover, the number of transmitters of uplink traffic mayoften be more than the number of transmitters of downlink traffic. Thus,it may be harder to coordinate the several transmitters of uplinktraffic in a distributed manner with low overhead. ERB may be used toresolve contentions and collisions between transmitters of uplinktraffic in a simple and distributed manner. Moreover, since uplinktraffic flows may often be less heavy, wireless devices are believed tonot suffer from the disadvantages of ERB that occur during high trafficcongestion. Thus, the above embodiment could be useful in wirelessnetworks that are used to access the Internet, such as single-hopwireless networks and multi-hop cellular networks.

As mentioned before, when heavier flows are scheduled moredeterministically, better coordination and cooperation may be achievedbetween transmitters of downlink frames. This coordination andcooperation may then be used to allow multiple interfering transmissionsto happen in parallel to improve the performance of wireless networks.Additionally, the above embodiment may be used to mitigate hidden nodeproblems by exploiting the determinism of heavier flows.

FIG. 20 is a generalized diagrammatic view of wireless transmissions bywireless terminals in accordance with an embodiment of the presentinvention, and FIG. 21 illustrates a process by which some of thesewireless transmissions may occur. In FIGS. 20, N1, N2, N3, and N4represent four different wireless terminals wirelessly communicating indifferent wireless environments and use cases. In particular, FIG. 20describes the hidden node problem and how it could be mitigated. FIG. 20depicts an example scenario; however, the described techniques couldeasily be applied to other scenarios. Event 2002 shows that wirelessterminal N1 can, in the illustrated example, only be heard by wirelessterminal N2 (as indicated by the circle around wireless terminal N1[e.g., circle around wireless terminal N1 may indicate the broadcastrange of N1; circle around wireless terminal N1 may indicate the rangewithin which transmissions from N1 can be carrier-sensed by otherwireless terminals; etc.]) and wireless terminal N4 can, in theillustrated example, only be heard by wireless terminal N3 (as indicatedby the circle around wireless terminal N4 [e.g., circle around wirelessterminal N4 may indicate the broadcast range of N4; circle aroundwireless terminal N4 may indicate the range within which transmissionsfrom N4 can be carrier-sensed by other wireless terminals; etc.]). Event2012 shows that wireless terminal N2 can, in the illustrated example, beheard by wireless terminal N1 and wireless terminal N3 (as indicated bythe circle around wireless terminal N2 [e.g., circle around wirelessterminal N2 may indicate the broadcast range of N2; circle aroundwireless terminal N2 may indicate the range within which transmissionsfrom N2 can be carrier-sensed by other wireless terminals; etc.]). Event2012 also shows that wireless terminal N3 can, in the illustratedexample, be heard by wireless terminal N2 and wireless terminal N4 (asindicated by the circle around wireless terminal N3 [e.g., circle aroundwireless terminal N3 may indicate the broadcast range of N3; circlearound wireless terminal N3 may indicate the range within whichtransmissions from N3 can be carrier-sensed by other wireless terminals;etc.]). Thus, terminals N1 and N4 are hidden from one another, and eachfrom N3 and N2, respectively. This relationship is potentially aproblem, particularly when a medium is shared among the terminals N1,N2, N3, and N4, because terminals that are hidden from one another areat risk of transmitting with the same resources as a given terminal,thereby causing signals to collide and potentially be lost by thereceiving N1 and N4 are transmitters of downlink traffic (as indicatedby the direction of arrows) and N2 and N3 are transmitters of uplinktraffic. N1 uses the asymmetric schedule 2062 and has chosen thedownlink mini-slot D1 to transmit downlink frames. N4 uses theasymmetric schedule 2062 and has chosen the downlink mini-slot D2 totransmit downlink frames. request-to-send (RTS) wireless signal from thetransmitter to a receiver, a signal which notifies the receiver that atransmitter wants to send (e.g., has data in an output buffer, causingit to transmit) something to it (the receiver) in the near future. Thereceiver receives the RTS signal, and in response, determines whetherthe receiver can receive a transmission. If the receiver estimates thatit can receive subsequent transmissions from the transmitter, thereceiver, in response, transmits a clear-to-send (CTS) wireless signalto the transmitter. The transmitter may then, in response to the CTSsignal, transmit data frames to the receiver. If (e.g., if and only if)the receiver receives the subsequent data frames correctly, it maytransmit, in response, an acknowledgment (ACK) to the transmitter. Thisprocedure is sometimes used by the IEEE 802.11n standard.

Event 2022 shows that N1 sends an RTS to N2 in mini-slot D1 and N4 sendsan RTS to N3 in mini-slot D2 in accordance with previously describedschedule 2062. Event 2032 shows that N2 sends (wirelessly transmits) aCTS to N1 after receiving the RTS. Note that, in this scenario, N2 isable to send a CTS to N1 before N3 can send a CTS to N4 because N2receives its RTS before N3 receives its RTS. Both N3 and N1 receive theCTS signal from N2, and in response, N3 defers transmission of its CTSto N4 (and/or N3 transmits a wireless signal to N4 to indicate thepresence of a potential hidden node) because it (N3) does not want to(e.g., is programmed or otherwise configured to avoid) interfere withthe transmissions happening between N1 and N2. N3's cooperation therebyallows N1 to send data frames to N2.

Event 2042 shows that N2 sends an ACK wireless signal back to N1 afterreceiving data frame(s) correctly from N1, thereby acknowledgingreceipt. N3 takes its cue from this ACK and intelligently (in responseto the ACK) sends a CTS back to N4 in deterministic downlink mini-slotD2 in event 2052. This intelligently delayed CTS is labeled as iCTS inevent 2052 of FIG. 20. N4 receives this delayed CTS and resumestransmission of data frames that it has buffered for N3. Since N1 usedD1, it must (in this embodiment) use downlink mini-slot D1* in thecurrent round of downlink transmissions for any further downlinktransmissions. Even if N1 sends out an RTS in D1*, N2 (e.g. aCTS-transmitter module inside N2) will (in this embodiment) delay (e.g.,in response to overhearing an iCTS wireless signal sent by N3 to N4) itsCTS (e.g., until N3 sends an ACK wireless signal back to N4 afterreceiving data frame(s) correctly from N4) to N1 (and/or N2 transmits awireless signal to N1 to indicate the presence of a potential hiddennode) in order to cooperate with N3 and prevent interfering with thetransmissions happening between N4 and N3. This is similar to thecooperation from N3 in event 2032.

Thus, the example of FIG. 20 shows an example scenario in which theintelligent CTS helps mitigate hidden node problems. Please note that N1is, in this example, hidden from N3 and N4 in the sense that N1 does notreceive the RTS signal from N4 and the CTS signal from N3. Moreover, N4is hidden from N2 and N1 in the same sense. Nonetheless, N1, N2, N3 andN4 are able to cooperate and coordinate using the intelligent CTSmechanism. Another thing to note is that the intelligent CTS mechanismbenefits from (but is not limited to) the deterministic schedule beingused for downlink frames by N1 and N4. When these downlink flows areheavy, hidden node problems may be mitigated for the flows that needmore protection. Intelligent CTS-like wireless signals may not always bedelayed. Sometimes they may be sent without delay but with an indication(e.g., a busy bit that is set, a wireless signal indicating the presenceof a potential hidden node, etc.) that shows that currently the receivercannot receive subsequent data frames. When a wireless terminal receivesa CTS-like wireless signal with such an indication, it may try againlater without getting penalized (e.g., by a collision resolutionmechanism such as exponential randomized back-off [ERB]). Severe hiddennode problems may exist even when only one flow is heavy. When the heavyflow is deterministically scheduled, intelligently timed CTS-likewireless signals (along with carrier-sensing) may be used to mitigatehidden node problems. Moreover, (in some embodiments) flows that sufferfrom hidden node problems may converge to a more deterministic schedule.Initially, RTS and CTS wireless signals may help in understanding thewireless environment and beacons (or beacon-like wireless signals) mayhelp in estimating the topologies of nearby nodes. Once a deterministicscheduling strategy is established, use of RTS and CTS wireless signalsmay be adaptively reduced. Wireless terminals may be allowed tocooperate, coordinate, and coexist with each other using the aboveembodiments. Such cooperation may help the wireless terminals toconverge to a favorable scheduling strategy over time.

The above described ACK, RTS, CTS, and intelligent CTS signals occur inthe MAC layer in the OSI model of network communication, which thoseskilled in the art will appreciate is different from signals havingsimilar names in other layers, such as TCP ACK signals in the transportlayer in the OSI model of network communication. In wireless networksused to access the Internet, often uplink transmissions may consist ofsmall frames (e.g., TCP ACKs in the transport layer). Small frames(e.g., TCP ACKs) may be (e.g., after being removed from an output bufferin a wireless device) aggregated (e.g., by a frame-aggregator-module ina wireless device) before transmission to reduce the number of uplinktransmissions. Aggregated frames (e.g., after being written into anoutput buffer in a wireless device) may then be transmitted. This mayhelp in reducing contentions and collisions between transmitters ofuplink traffic even during times of heavy usage. Frame aggregation(e.g., of small frames) may depend on a threshold (e.g., asize-threshold that may keep the probability of frame collisions below acertain collision-threshold, a timeout-threshold that may prevent TCP'scongestion control from kicking in, etc.). In some embodiments, frames(e.g., uplink, downlink, large, small, etc.) at various layers in theOSI model of network communication may be aggregated beforetransmission.

A transmitter of heavy traffic may, in some embodiments, get moredeterministic mini-slots than a light transmitter depending onqueue-lengths, bandwidth needs, average throughput, and peak throughput.RTS and CTS frames (e.g., wireless signals) may help mitigate the hiddennode problem in random-access wireless networks, though not allembodiments use this technique or use this technique to this effect.However, it may take much longer than a mini-slot-time to receive andact in response to receiving an RTS or CTS frame. This may lead to areduction in the benefits of using RTS and CTS frames. The aboveembodiment may help select asymmetric schedules that may increase thebenefits of control frames (e.g., RTS and CTS frames). For example, afirst wireless device and a second wireless device need to transmit alarge amount of downlink frames; the first wireless device ispre-assigned a first downlink mini-slot (e.g., by aschedule-selector-module in the first wireless device) in a firstasymmetric schedule (e.g., asymmetric schedule 1649 in FIG. 16); asecond downlink mini-slot is adjacent to the first downlink mini-slot inthe first asymmetric schedule (e.g., D2 is adjacent to D1 in asymmetricschedule 1649 in FIG. 16); in response to sensing (e.g., by awireless-proximity-sensing-module in the second wireless device)wireless proximity (e.g., two wireless devices may be considered to havewireless proximity if transmissions from one wireless device are oftenreceived with a high signal-quality [e.g., SINR of greater than 20 dB]by the other wireless device), the second wireless device is assignedthe second downlink mini-slot (e.g., by a schedule-selector-module inthe second wireless device) in the first asymmetric schedule. The firstwireless device and the second wireless device may suffer from fewerhidden node problems due to their wireless proximity; thus, utilization(i.e. by the first wireless device and the second wireless device) ofadjacent downlink mini-slots for transmitting downlink frames may notreduce the effectiveness of control frames (e.g., RTS and CTS frames).For example, a third wireless device and a fourth wireless device needto transmit a large amount of downlink frames; the third wireless deviceis pre-assigned a third downlink mini-slot (e.g., by aschedule-selector-module in the third wireless device) in a secondasymmetric schedule (e.g., asymmetric schedule 1649 in FIG. 16); afourth downlink mini-slot is far apart in time from the third downlinkmini-slot in the second asymmetric schedule (e.g., D8 is far apart intime from D1 in asymmetric schedule 1649 in FIG. 16); in response tosensing (e.g., by a wireless-proximity-sensing-module in the fourthwireless device) lack of wireless proximity (e.g., two wireless devicesmay be considered to have lack of wireless proximity if transmissionsfrom one wireless device are often received with a low signal-quality[e.g., SINR of less than 20 dB] by the other wireless device; twowireless devices may be considered to have lack of wireless proximity iftransmissions from one wireless device are often not received by theother wireless device; etc.), the fourth wireless device is assigned thefourth downlink mini-slot (e.g., by a schedule-selector-module in thefourth wireless device) in the second asymmetric schedule. The thirdwireless device and the fourth wireless device may suffer from morehidden node problems due to their lack of wireless proximity; thus,utilization (i.e. by the third wireless device and the fourth wirelessdevice) of downlink mini-slots that are far apart in time fortransmitting downlink frames may improve the effectiveness of controlframes (e.g., RTS and CTS frames).

In some embodiments, MAC addresses may be curtailed for subsequent RTSor CTS wireless-signals (e.g., data-frames, control-frames,beacon-frames, management-frames, etc.) so that subsequent RTS or CTSwireless-signals are able to fit within fewer multiples ofmini-slot-time. MAC addresses may be adaptively curtailed until errors(e.g. frame-error-rate exceeds 10%, frame-error-rate exceeds 20%, etc.)start happening. Variable length MAC addresses may be positioned withdelimiters or towards the end of frame to facilitate decoding andprocessing.

In some embodiments, ordering of parallel transmissions may dictate thetransmit power level required for the receiver to be able to lock ontoand decode desired frame (amongst those being transmitted in parallel).In some embodiments, choice of transmit power levels may not only dependon the SINR, SNR, and minimum receiver level sensitivity for thephysical-layer rates being used, but also on the exact ordering ofparallel transmissions. For example, when using deterministic slots thattransmit in parallel using channel measurement algorithms, the orderingof parallel transmissions may dictate the required transmit power levelto satisfy locking and SINR requirements of the receiver. In someembodiments, the deterministic slots in asymmetric scheduling modes mayallow earlier downlink transmitters to predict transmit power levelsthat may be required in the presence of future parallel downlinktransmitters.

In another embodiment of the present invention, a method for improvingthe performance of a wireless network is provided. The method includes afirst wireless device receiving support from a second wireless deviceand a third wireless base-station. The third wireless base-station mayroute traffic for the first wireless device via the second wirelessdevice when beneficial. Moreover, the first wireless device may routetraffic for the third wireless base-station via the second wirelessdevice when beneficial. The third wireless base-station may also requestsupport from the second wireless device when communicating with thefirst wireless device. Furthermore, the first wireless device mayrequest support from the second wireless device when communicating withthe third wireless base-station.

In the above described embodiment, the second wireless device maydetermine whether to provide support to the first wireless device basedon at least one of the following factors: quality of nearby sinks andrelays, quantity of nearby sinks and relays, battery life, source ofpower, average throughput, bandwidth usage, bandwidth needs, bandwidthavailability, type of device, level of mobility, time of day,subscription fees, user profile, non-cellular signal strength andquality, cellular signal strength and quality, level of wirelessinterference seen by a non-cellular interface, level of wirelessinterference seen by a cellular interface, number of hops to a sink,current state of the second device, current state of the first device,participation policy being used by the second wireless device,participation policy being used by the first wireless device, andsurrounding wireless environment. For example, each of, or a subset of,these factors may be compared against respective threshold values orcategories and if a factor satisfies the threshold or falls in acategory, the device may choose to provide support to the first wirelessdevice and if the threshold is not met or the category is inapplicable,the device may not choose to provide support to the first wirelessdevice.

In the above embodiment, the first wireless device may request supportfrom the second wireless device and the third wireless base-station,wherein cost of support depends on at least one of the following: time,date, subscription fees, user profile, network conditions, networkcongestion, location, surrounding wireless environment, spot price,average price, nightly price, and monthly price. Adding the dimension ofcost to requesting, granting, receiving, and giving support may createimportant economic incentives for wireless terminals to cooperate witheach. Such cooperation may be useful for wireless terminals and wirelessnetworks. For example, a subscriber paying higher subscription fees maybe able to request frequent and heavy cooperation from nearby wirelessterminals. For example, during peak hours, requesting and receivingsupport may have a high spot price. Also, during peak hours, grantingand giving support may have a high reward associated with it. Such costand reward information may be made available to users, wireless devices,wireless base-stations, and wireless network operators in real-time.

FIGS. 7A-7D are generalized diagrammatic views of an example cell in acellular network where wireless devices in the cell have the ability tocooperate with each other and the base station via multi-hopping inaccordance with an embodiment of the present invention. In scenario 702of FIG. 7A, wireless device 704 is seeing an upfade from the cellulartower 712 and wireless devices 706 and 708 are seeing a downfade fromthe cellular tower 712. An upfade happens when at a given instant intime and/or frequency, a receiver receives a transmitters signal at ahigh signal-to-interference-and-noise-ratio (SINR) or highsignal-to-noise-ratio (SNR). A downfade happens when at a given instantin time and/or frequency, a receiver receives a transmitters signal at alow signal-to-interference-and-noise-ratio (SINR) or lowsignal-to-noise-ratio (SNR). Without any cooperation between thewireless devices and the cellular tower, in many systems, the only wayfor wireless device 706 to communicate with the cellular network isdirectly over a single hop. As shown in scenario 702, such a limitationmay cause devices to experience a low data-rate while using a givenamount of wireless spectrum because of the downfade. In scenario 720 ofFIG. 7B, wireless device 722 is seeing an upfade from the cellular tower730 and wireless devices 724 and 726 are seeing a downfade from thecellular tower 730. If cellular tower 730 is capable of routing downlinktraffic to wireless device 724 via wireless device 722, it may support ahigher data-rate using the same amount of spectrum as in scenario 702because device 722 is experiencing an upfade from the cellular tower730. In scenario 740 of FIG. 7C, wireless device 744 is seeing an upfadefrom the cellular tower 750 and wireless devices 742 and 746 are seeinga downfade from the cellular tower 750. Thus, in scenario 740, cellulartower 750 may directly send downlink traffic to wireless device 744 andmay still support a higher data-rate using the same amount of spectrumas in scenario 702. This is because device 744 is experiencing an upfadefrom the cellular tower 750. In scenario 760 of FIG. 7D, wireless device766 is seeing an upfade from the cellular tower 770 and wireless devices762 and 764 are seeing a downfade from the cellular tower 770. Ifcellular tower 770 is capable of routing downlink traffic to wirelessdevice 764 via wireless device 766, the network may support a higherdata-rate using the same amount of spectrum as in scenario 702 becausedevice 766 is experiencing an upfade from the cellular tower 770. Thisexample is one way in which wireless terminals and the wireless networkmay benefit from the capability to receive support from each other.

Algorithmic support from different parts of the cellular network isexpected to be useful, in some systems, for single-hop and multi-hopcellular networks. Such support may facilitate cooperative routing,cooperative scheduling, reliability, and throughput enhancements.Algorithmic support could come from the base-transceiver-system (BTS),base-station-controller (BSC), radio-network-controller (RNC),mobile-switching-center (MSC), and other wireless terminals. Suchalgorithmic support could enhance user experience and networkperformance by, for example, enabling several use-cases andapplications. For example, the example shown in FIG. 7 could benefitfrom such routing algorithmic support from the cellular base-station.Note that different wireless devices in FIG. 7 may see severe upfadesand downfades at different times and frequencies because of multi-patheffects, shadowing effects, and mobility of the car. Billing supportfrom MSC may be required, in some systems, to allocate different costsand rewards for receiving and granting support. Amount of supportreceived or granted may be based on subscription fees, user profiles,user preferences, and multi-hop participation policies. Algorithmicsupport and cooperation between wireless terminals may beinduced/initiated/enabled by wireless devices, wireless base-stations,wireless networks, and core networks.

Users may often use the cellular network without knowing much about thecurrent state of the cellular network. For example, there may be severecongestion in the cell of a cellular network, and if cellular devicesconstantly keep trying to access the cellular network, the congestionmay get worse. This may reduce performance for everyone. If wirelessterminals have the capability of cooperating with each other and thecore network, wireless devices may be configured to access the cellularnetwork based on the state of the network to satisfy the needs ofend-users. The above embodiment may be used to executed by applicationsoftware that senses network state and network congestion usingalgorithmic support from nearby wireless terminals and the core networkof the cellular operator. Moreover, the application software may collectusers requests to access the cellular network. Using available networkstate and network congestion information, the application software maythen transmit/receive data to/from the network in a way that maymitigate network congestion (e.g., based on congestions) and notexcessively hurt user-experience. For example, delay sensitive data suchas voice may be exchanged with the cellular network without much delay.However, requests to download files and buffer video may be delayed tobalance the congestion in the network and may help the network operatein a stable state. Moreover, the delay in accessing the cellular networkmay be hidden from end-users by clever user-interface design. Moreover,such cooperation and coordination between wireless terminals and thecellular operator's core-network may improve overall networkperformance. Thus, the end-user may see a gain in user experience andperformance. The application software using the above embodiment may askfor multiple requests (requiring network access) at a time from the userand then opportunistically use the network using knowledge of macro andmicro network environment. Such functionality may include providing HTTPdata to a web browser being used by the user when such data becomesavailable at the convenience of the network. Algorithmic support fromother wireless terminals and the operator's core-network may simplifythe design of the human-interface of such an application and may make itappear to the end-user as though the latency is low. Furthermore,network efficiency may increase, and congestion may decrease as wasexplained above. This may be useful for wireless networks during timesof peak usage and heavy congestion. Network access that can be delayedby a significant amount may also be relevant. For example, backing up oflarge databases may be delayed till nighttime when network congestionmay be low and enough network capacity may be available. Algorithmicsupport from other wireless terminals and the operator's core-networkmay allow a wireless device to start, pause, and resume backups.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a first wireless terminal determining whether to send data to athird wireless terminal via a second wireless terminal based on at leastone of the following factors: whether signal-quality of transmissionsmade by the third wireless terminal and received by the first wirelessterminal are above a first threshold (e.g. the threshold may range from0 dB to 50 dB); and whether signal-quality of transmissions made by thesecond wireless terminal and received by the first wireless terminal areabove a second threshold (e.g. the threshold may range from 0 dB to 50dB). Moreover, in some embodiments, the first threshold may depend onsignal-quality of transmissions made by the second wireless terminal andreceived by the first wireless terminal. Furthermore, in someembodiments, the second threshold may depend on signal-quality oftransmissions made by the third wireless terminal and received by thefirst wireless terminal. Such an approach is believed to mitigatehidden-node problems in some applications.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a first wireless terminal determining whether to send data to athird wireless terminal via a second wireless terminal based on at leastone of the following factors: whether signal-quality of transmissionsmade by the third wireless terminal and received by the first wirelessterminal are above (below) a first threshold; and whether signal-qualityof transmissions made by the second wireless terminal and received bythe first wireless terminal are above (below) a second threshold.Moreover, in some embodiments, the first threshold may depend onsignal-quality of transmissions made by the second wireless terminal andreceived by the first wireless terminal. Furthermore, in someembodiments, the second threshold may depend on signal-quality oftransmissions made by the third wireless terminal and received by thefirst wireless terminal. Such an approach is believed to mitigatehidden-node problems in some applications.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a second wireless terminal determining whether to allow a firstwireless terminal to send data to a third wireless terminal via thesecond wireless terminal based on at least one of the following factors:whether signal-quality of transmissions made by the third wirelessterminal and received by the second wireless terminal are above a firstthreshold (e.g. the threshold may range from 0 dB to 50 dB); and whethersignal-quality of transmissions made by the first wireless terminal andreceived by the second wireless terminal are above a second threshold(e.g. the threshold may range from 0 dB to 50 dB). Moreover, in someembodiments, the first threshold may depend on signal-quality oftransmissions made by the first wireless terminal and received by thesecond wireless terminal. Furthermore, in some embodiments, the secondthreshold may depend on signal-quality of transmissions made by thethird wireless terminal and received by the second wireless terminal.Such an approach is believed to mitigate hidden-node problems in someapplications.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a second wireless terminal determining whether to allow a firstwireless terminal to send data to a third wireless terminal via thesecond wireless terminal based on at least one of the following factors:whether signal-quality of transmissions made by the third wirelessterminal and received by the second wireless terminal are above (below)a first threshold; and whether signal-quality of transmissions made bythe first wireless terminal and received by the second wireless terminalare above (below) a second threshold. Moreover, in some embodiments, thefirst threshold may depend on signal-quality of transmissions made bythe first wireless terminal and received by the second wirelessterminal. Furthermore, in some embodiments, the second threshold maydepend on signal-quality of transmissions made by the third wirelessterminal and received by the second wireless terminal. Such an approachis believed to mitigate hidden-node problems in some applications.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a third wireless terminal determining whether to allow a firstwireless terminal to send data to the third wireless terminal via asecond wireless terminal based on at least one of the following factors:whether signal-quality of transmissions made by the first wirelessterminal and received by the third wireless terminal are above a firstthreshold (e.g. the threshold may range from 0 dB to 50 dB); and whethersignal-quality of transmissions made by the second wireless terminal andreceived by the third wireless terminal are above a second threshold(e.g. the threshold may range from 0 dB to 50 dB). Moreover, in someembodiments, the first threshold may depend on signal-quality oftransmissions made by the second wireless terminal and received by thethird wireless terminal. Furthermore, in some embodiments, the secondthreshold may depend on signal-quality of transmissions made by thefirst wireless terminal and received by the third wireless terminal.Such an approach is believed to mitigate hidden-node problems in someapplications.

In another embodiment of the present invention, a method for routing ina wireless network is provided. The method, in some embodiments,includes a third wireless terminal determining whether to allow a firstwireless terminal to send data to the third wireless terminal via asecond wireless terminal based on at least one of the following factors:whether signal-quality of transmissions made by the first wirelessterminal and received by the third wireless terminal are above (below) afirst threshold; and whether signal-quality of transmissions made by thesecond wireless terminal and received by the third wireless terminal areabove (below) a second threshold. Moreover, in some embodiments, thefirst threshold may depend on signal-quality of transmissions made bythe second wireless terminal and received by the third wirelessterminal. Furthermore, in some embodiments, the second threshold maydepend on signal-quality of transmissions made by the first wirelessterminal and received by the third wireless terminal. Such an approachis believed to mitigate hidden-node problems in some applications.

Some embodiments of the above invention may improve the performance ofmulti-hop wireless networks by enabling wireless terminals (e.g., amulti-hop-route-selector-module in the wireless terminals) to determinemulti-hop routes based on one or more topological factors (e.g.,signal-quality, path-loss, relative wireless direction, absolutewireless direction, etc.). A first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may estimatethe topology of nearby wireless terminals (e.g., a second wirelessterminal, a third wireless terminal, etc.) to facilitate determination(e.g., by a multi-hop-route-selector-module in the first wirelessterminal) of multi-hop routes (e.g. consisting of the first wirelessterminal, a second wireless terminal, and a third wireless terminal). Insome embodiments, topology estimation may provide the first wirelessterminal an indication of the signal-quality (e.g., SINR of 10 dB, SINRof 20 dB, etc.) of wireless signals (e.g., beacon-frame, data-frames,management-frames, control-frames, etc.) received from nearby wirelessterminals. In some embodiments, a wireless signal (e.g., beacon-frame,data-frames, management-frames, control-frames, etc.) may include anindication (e.g., data indicative of the absolute transmit power-levelused by a second wireless terminal may be included in the wirelesssignal by the transmit-power-module in the second wireless terminal) ofthe absolute transmit power-level (e.g., 10 dBm, 20 dBm, etc.) used by anearby wireless terminal (e.g., a second wireless terminal) whentransmitting the wireless signal. When the first wireless terminalreceives the wireless signal, based (e.g., ratio of the absolutetransmit power-level and the signal-quality) on the indication of theabsolute transmit power-level and the signal-quality (e.g.,received-signal-strength-indication [RSSI], signal-to-noise-ratio [SNR],signal-to-interference-and-noise-ratio [SINR], channel-quality-indicator[CQI], etc.) with which the wireless signal was received at the firstwireless terminal, the first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may measurethe path-loss (e.g., path-loss may range from 0 dB to 100 dB) orchannel-loss (e.g., channel-loss may range from 0 dB to 100 dB) betweenthe transmitter of the wireless signal and the first wireless terminal.The measured path-loss or channel-loss estimate may then be used insteadof the signal-quality to select multi-hop routes. In some embodiments,the first wireless terminal may have several radio antennas. When thefirst wireless terminal receives a wireless signal (e.g., from a secondwireless terminal), the first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may measurethe relative wireless direction (e.g., relative direction from whichwireless signals transmitted by a second wireless terminal are receivedat the first wireless terminal with high signal-quality) of thetransmitter (e.g., a second wireless terminal) of the wireless signalbased on at least one of the following: the beam-forming weights used bythe transmitter of the wireless signal; and the received signal at eachof the radio antennas of the first wireless terminal (e.g.,corresponding to the parameters used for maximal-ratio-combining at thefirst wireless terminal when receiving the wireless signal. In someembodiments, if the absolute orientation of the radio antennas of thefirst wireless terminal is known (e.g., in a general-purpose processor[e.g., CPU] in the first wireless terminal; in the computer programproduct being executed in the first wireless terminal; in the memory ofthe first wireless terminal, etc.), the first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may determinethe absolute wireless direction (e.g., by using the relative wirelessdirection of a second wireless terminal and the absolute orientation ofthe radio antennas of the first wireless terminal) of the transmitter ofa wireless signal (e.g., a second wireless terminal) at the firstwireless terminal.

FIG. 8 is a flowchart of a method for routing in a wireless network inaccordance with an embodiment of the present invention. In step 804, afirst wireless terminal determines whether to send data to a thirdwireless terminal via a second wireless terminal based on at least oneof the following factors: whether signal-quality of transmissions madeby the third wireless terminal and received by the first wirelessterminal are above a first threshold; and whether signal-quality oftransmissions made by the second wireless terminal and received by thefirst wireless terminal are above a second threshold. In step 806, thefirst wireless terminal makes the actual determination. If the firstwireless terminal determines to send data to the third wireless terminalvia the second wireless terminal, the first wireless terminal sends(wirelessly transmits) data to the third wireless terminal via thesecond wireless terminal in step 810.

Some embodiments of the above invention may improve the performance ofmulti-hop wireless networks by enabling wireless terminals (e.g., amulti-hop-route-selector-module in the wireless terminals) to determineefficient multi-hop routes. For example, a first wireless terminal mayneed to communicate with a third wireless terminal. Signal-quality(e.g., obtained by a topology-estimation-module in the first wirelessterminal) of transmissions (e.g., wireless-signals, beacon-frames,data-frames, management-frames, control-frames, etc.) made by the thirdwireless terminal and received by the first wireless terminal may beabove a first threshold (e.g., the first threshold is 0 dB). However,signal-quality of transmissions made by the third wireless terminal andreceived by the first wireless terminal may be low (e.g., SINR of lessthan 10 dB); thus, the first wireless terminal (e.g., amulti-hop-route-selector-module in the first wireless terminal) maydetermine to communicate with the third wireless terminal via amulti-hop route (instead of a single-hop route). Signal-quality oftransmissions made by a second wireless terminal and received by thefirst wireless terminal may be above a second threshold (e.g., thesecond threshold is 30 dB). Signal-quality of transmissions made by afourth wireless terminal and received by the first wireless terminal maybe below the second threshold. The first wireless terminal (e.g., themulti-hop-route-selector-module in the first wireless terminal) may thendetermine (e.g., after obtaining at the first wireless terminal [e.g.,from the topology-estimation-module in the first wireless terminal] thesignal-quality of transmissions made by the second wireless terminal andthe third wireless terminal [and received at the first wirelessterminal]) to send wireless signals (e.g. data-frames) to the thirdwireless terminal via the second wireless terminal. Moreover, the firstwireless terminal (e.g., the multi-hop-route-selector-module in thefirst wireless terminal) may then determine (e.g., after obtaining atthe first wireless terminal [e.g., from the topology-estimation-modulein the first wireless terminal] the signal-quality of transmissions madeby the third wireless terminal and the fourth wireless terminal [andreceived at the first wireless terminal]) to not send wireless signals(e.g. data-frames) to the third wireless terminal via the fourthwireless terminal.

Again referring to FIG. 8, in step 822, a second wireless terminaldetermines whether to allow a first wireless terminal to send data to athird wireless terminal via the second wireless terminal based on atleast one of the following factors: whether signal-quality oftransmissions made by the third wireless terminal and received by thesecond wireless terminal are above a first threshold; and whethersignal-quality of transmissions made by the first wireless terminal andreceived by the second wireless terminal are above a second threshold.In step 824, the second wireless terminal makes the actualdetermination. If the second wireless terminal determines to allow thefirst wireless terminal to send data to the third wireless terminal viathe second wireless terminal, the first wireless terminal sends(wirelessly transmits) data to the third wireless terminal via thesecond wireless terminal in step 828.

Some embodiments of the above invention may improve the performance ofmulti-hop wireless networks by enabling wireless terminals (e.g., amulti-hop-route-selector-module in the wireless terminals) to determineefficient multi-hop routes. For example, a first wireless terminal and afourth wireless terminal may need to communicate with a third wirelessterminal via a second wireless terminal. Signal-quality (e.g., obtainedby a topology-estimation-module in the second wireless terminal) oftransmissions (e.g., wireless-signals, beacon-frames, data-frames,management-frames, control-frames, etc.) made by the third wirelessterminal and received by the second wireless terminal may be above afirst threshold (e.g., the first threshold is 30 dB). Signal-quality oftransmissions made by the first wireless terminal and received by thesecond wireless terminal may be above a second threshold (e.g., thesecond threshold is 30 dB). Signal-quality of transmissions made by thefourth wireless terminal and received by the second wireless terminalmay be below the second threshold. The second wireless terminal (e.g.,the multi-hop-route-selector-module in the second wireless terminal) maythen determine (e.g., after obtaining at the second wireless terminal[e.g., from the topology-estimation-module in the second wirelessterminal] the signal-quality of transmissions made by the first wirelessterminal and the third wireless terminal [and received at the secondwireless terminal]) to allow the first wireless terminal to sendwireless signals (e.g. data-frames) to the third wireless terminal viathe second wireless terminal. Moreover, the second wireless terminal(e.g., the multi-hop-route-selector-module in the second wirelessterminal) may then determine (e.g., after obtaining at the secondwireless terminal [e.g., from the topology-estimation-module in thesecond wireless terminal] the signal-quality of transmissions made bythe third wireless terminal and the fourth wireless terminal [andreceived at the second wireless terminal]) to disallow the fourthwireless terminal to send wireless signals (e.g. data-frames) to thethird wireless terminal via the second wireless terminal.

Some embodiments of the above invention may mitigate hidden nodeproblems by enabling wireless terminals to find efficient multi-hopwireless routes. Such efficient multi-hop wireless routes may consist ofwireless terminals that can carrier-sense (e.g. SNR greater than 0 dB)each other. Moreover, such multi-hop routes may allow RTS and CTSwireless signals to be more effective (for the multi-hop route) becausewireless terminals (comprising the multi-hop route) will at least beable to carrier-sense the RTS and CTS wireless signals. Channelmeasurement schemes that allow multiple interfering flows to happen inparallel when feasible may have more information (e.g. multi-hop routinginformation) available and thus may benefit from the above invention.Wireless terminals (comprising the multi-hop route) may also providefeedback to each other so that each wireless terminal could adjust itstransmit power-level to facilitate the above embodiment (e.g. a firstwireless terminal adjusting its transmit power-level to satisfy a firstthreshold at a second wireless terminal and a second threshold at athird wireless terminal).

In some embodiments, transmit power-level used by a first wirelessterminal to transmit RTS frames may depend on a parameter (e.g., such asa parameter that depends on the gap between the average SINR required todecode the RTS frame and the SINR at which the RTS frame is received ata receiver). Furthermore, the transmit power-level used by the firstwireless terminal to transmit RTS frames may indicate to other wirelessterminals to not transmit in parallel and may mitigate interference fromthe other wireless terminals.

In another embodiment of the present invention, a method for managingvehicular traffic is provided. The method, in some embodiments, includesa first wireless terminal sending a beacon. The method further includesa second wireless terminal receiving the beacon and sending a part ofthe beacon to a traffic-light controller. In addition, the methodfurther includes the traffic-light controller receiving the part of thebeacon and using it to do at least one of the following: monitorvehicles, regulate vehicles, route vehicles, control vehicles, monitorpeople, regulate people, route people, control people, and controltraffic lights. Moreover, the first wireless terminal may be one of thefollowing: a vehicle, a device embedded in a vehicle, a person, and adevice carried by a person. Furthermore, the second wireless terminalmay be co-located with the traffic-light controller. Also, thetraffic-light controller may communicate with other traffic-lightcontrollers to better manage vehicular traffic. In addition, the beaconmay include information about at least one of the following: type of thefirst wireless terminal, intention of the first wireless terminal, andnumber of wireless terminals near the first wireless terminal. Insteadof beacons, the first wireless terminal may use other means of wirelesscommunication signaling to communicate with the second wireless terminaland the traffic-light controller.

FIG. 9 is a flowchart of a method for managing vehicular traffic and amethod for conserving energy in accordance with an embodiment of thepresent invention. In step 904, a first wireless terminal sends(wirelessly transmits) a beacon. In step 906, a second wireless terminalreceives the beacon and sends a part of the beacon to a traffic-lightcontroller. In step 908, the traffic-light controller receives the partof the beacon and uses it to do at least one of the following: monitorvehicles, regulate vehicles, route vehicles, control vehicles, monitorpeople, regulate people, route people, control people, and controltraffic lights.

FIG. 10 is a generalized diagrammatic view of a transportation systemwhere the transportation system has the ability to detect the presenceof vehicles in accordance with an embodiment of the present invention.Key 1002 shows symbols corresponding to the first wireless terminal, thesecond wireless terminal, the traffic-light controller, wirelessbeacons, and wired/wireless links. The regional traffic-light controllerhas either a wired or wireless network connection with severaltraffic-lights and traffic-light intersections. Such a wired or wirelessnetwork connection may be used to exchange data between the regionaltraffic-light controller and the traffic-lights. Such data may be usedto monitor, regulate, control, and route vehicular and pedestriantraffic. Traffic-light intersection 1022 is one of several in theregion. Traffic-lights 1024 regulate traffic at traffic-lightintersection 1022. Traffic-lights 1024 and traffic-light intersection1022, in this embodiment, are connected over a wired or wireless link1030 to the regional traffic-light controller 1004. This link may be acellular connection. Vehicle (or pedestrian) 1028 occasionally (e.g.,periodically) transmits beacons 1026. These could be received by thetraffic-lights 1024. Traffic-lights 1024 may collect beacons from othernearby vehicles and pedestrians as well. While vehicles may be installedwith wireless subsystems, pedestrians may be carrying mobile wirelessdevices. Beacons transmitted by vehicles and pedestrians may be used tomonitor, regulate, control, and route vehicles, automobiles,pedestrians, animals, and machines. Beacons may also include intentionof a vehicle or pedestrian, such as an intent to turn left, turn right,compass heading, urgency, emergency, and other special situations.Wireless terminals that have overlapping functionality with the firstwireless terminal could aggregate information about nearby vehicles orpedestrians and include that information in the beacons that theytransmit. Wireless terminals that have overlapping functionality withthe first wireless terminal could aggregate information about nearbyvehicles or pedestrians in a specific direction and include thatinformation in the beacons that they transmit. Moreover, traffic-lightsmay use crowd-sourcing techniques when aggregating information collectedfrom beacons to reduce errors. Traffic-lights may also includeconfidence values and sample sizes for the gathered information toindicate reliability information. After collecting and aggregating theinformation received via beacons and other wireless communicationsignaling from nearby vehicles and pedestrians, traffic-lights andtraffic-light intersections could send the information to the regionaltraffic-light controller. The traffic-lights may retain and send onlycertain parts of beacons and use dimensionality reduction techniqueswithout causing loss of useful information. While sending entire chunksof information gathered from the various vehicles and pedestrians to theregional traffic-light controller may be useful, choosing useful partsmay help save network bandwidth. The regional traffic-light controllermay receive localized real-time information from vehicles andpedestrians in this way over wired and wireless links. The regionaltraffic-light controller may then use this information to communicatewith other traffic-light controllers to come up with a better trafficrouting schedule given the current levels of congestion, needs ofvehicles and pedestrians, time of day, complexity of solution, safety ofimplementation and deployment of new routing schedule, and reliabilityof information gathered. If a better traffic and pedestrian routingschedule is established for a localized region or a large-scale region,it could sent to the traffic-lights via the wired or wireless link.Traffic-lights may then work according to the new routing schedule. Thismay reduce traffic congestion on the roads. Moreover, this entireprocess could be repeated occasionally to adapt the traffic routingschedule to the changing conditions.

In another embodiment of the present invention, a method for conservingenergy is provided. The method, in some embodiments, includes a firstwireless terminal sending a beacon. The method further includes a secondwireless terminal receiving the beacon and sending a part of the beaconto an electric appliance controller. In addition, the method furtherincludes the electric appliance controller receiving the part of thebeacon and using it to do at least one of the following: detect people,monitor people, receive instructions, and control electric appliances.Moreover, the first wireless terminal could be one of the following: aperson or a device carried by a person. Furthermore, the second wirelessterminal could also be the electric appliance controller. Also, theelectric appliance controller could better conserve energy by using atleast one of the following characteristics of the first wirelessterminal: type, needs, and number.

FIG. 9 is a flowchart of a method for managing vehicular traffic and amethod for conserving energy in accordance with an embodiment of thepresent invention. In step 922, a first wireless terminal sends abeacon. In step 924, a second wireless terminal receives the beacon andsends a part of the beacon to an electric appliance controller. In step926, the electric appliance controller receives the part of the beaconand uses it to do at least one of the following: detect, monitor,regulate, guide, give instructions to, receive instructions from, andcontrol people, animals, wireless terminals, electric appliances,machines, other electric appliance controllers, electric grids, off-sitepower plants, and on-site power generation mechanisms.

In another embodiment of the present invention, a method for relaying ina wireless network is provided. In a multi-hop wireless network,wireless terminals (e.g., a first wireless terminal, a second wirelessterminal, etc.) comprising a multi-hop wireless route may incur delays(e.g., decoding-delays, processing-delays, etc.) when relayingwireless-signals on the multi-hop wireless route. Some embodiments ofthe above invention may reduce the delays (e.g., decoding-delays,processing-delays, etc.) incurred by the wireless terminals (e.g., afirst wireless terminal, a second wireless terminal, etc.) when relayingwireless-signals on the multi-hop wireless route. Moreover, someembodiments of the above invention may facilitate co-existence (e.g.,for scheduling purposes, for routing purposes, etc.) amongst wirelessdevices comprising one or more multi-hop wireless routes. The method, insome embodiments, includes a first wireless terminal (e.g., afast-relay-module in the first wireless terminal) calculating a firstvalue (e.g., the first value is 1-byte in size, the first value is4-byte s in size, etc.). The method further includes the first wirelessterminal transmitting a wireless-signal (e.g., beacon-frames,data-frames, management-frames, control-frames, etc.) along with thefirst value (e.g., data indicative of the first value may be included inthe wireless signal by the fast-relay-module in the first wirelessterminal) to a second wireless terminal. In addition, the method furtherincludes the second wireless terminal (e.g., a fast-relay-module in thesecond wireless terminal) receiving the wireless-signal (from the firstwireless terminal) and using the first value to do at least one of thefollowing: determining whether to relay the wireless-signal, choosingnext recipient of the wireless-signal, determining how to schedule thewireless-signal, determining how to route the wireless-signal, andcalculating a second value to replace the first value in thewireless-signal. Moreover, in some embodiments, the first value (e.g.,computed by the fast-relay-module in the first wireless terminal) andthe second value (e.g., computed by the fast-relay-module in the secondwireless terminal) may be based on (e.g., indicative of, hash functionof, etc.) at least one of the following: source address (e.g., sourceMAC-address, source IP-address, etc.) of the wireless-signal (e.g.,obtained from the MAC-header of the wireless-signal, obtained from theIP-header of the wireless-signal, etc.), destination address (e.g.,destination MAC-address, destination IP-address, etc.) of thewireless-signal (e.g., obtained from the MAC-header of thewireless-signal, obtained from the IP-header of the wireless-signal,etc.), relay address (e.g., relay MAC-address, relay IP-address, etc.)of the wireless-signal (e.g., obtained from the MAC-header of thewireless-signal, obtained from the IP-header of the wireless-signal,etc.), and traffic class (e.g., voice traffic, video traffic,best-effort traffic, background traffic, delay-sensitive traffic,jitter-sensitive traffic, etc.) of the wireless-signal (e.g., obtainedfrom the MAC-header of the wireless-signal, obtained from the IP-headerof the wireless-signal, etc.). Furthermore, in some embodiments, thefirst value and the second value may be included (e.g., by thefast-relay-module in the first wireless terminal, by thefast-relay-module in the second wireless terminal, etc.) in thephysical-layer portion (e.g., physical-layer preamble, physical-layerheader, etc.) of the wireless-signal.

FIG. 11 is a flowchart of a method for relaying in a wireless network inaccordance with an embodiment of the present invention. In step 1104, afirst wireless terminal calculates a first value. In step 1106, thefirst wireless terminal transmits a data frame along with the firstvalue to a second wireless terminal. In step 1108, the second wirelessterminal receives the data frame and the first value. In step 1110, thesecond wireless terminal determines whether to relay the data framebased on the first value. In step 1114, the second wireless terminaluses the first value to further choose the next recipient of the dataframe, schedule the data frame, route the data frame, and calculate asecond value to replace the first value. In step 1116, the secondwireless terminal replaces the first value with the second value andrelays the data frame to a third wireless terminal.

Some embodiments of the above invention may, for example, enable fastrelaying of data frames by computing (e.g., in the fast-relay-module inthe first wireless terminal) the first value based on (e.g., indicativeof, hash function of, etc.) certain parameters (e.g., the sourcemedium-access control (MAC) address [e.g., corresponding to the firstwireless terminal]; relay MAC-address [e.g., corresponding to the secondwireless terminal]; destination MAC-address [e.g., corresponding to thethird wireless terminal]; and traffic class [e.g., corresponding to thedata frame]; etc.) and then including (e.g., data indicative of thefirst value may be included in the data frame by the fast-relay-modulein the first wireless terminal) the first value in the physical-layerheader. Furthermore, in some embodiments, the first value may be smallin size (e.g., 1-byte, 4-bytes, etc.), may be modulated using thebase-rate (e.g., the lowest physical-layer rate in the IEEE 802.11nstandard), and may be indicative of cross-layer information (e.g.,scheduling information, routing information, etc.); thus, the firstvalue may reduce processing-delays (e.g., the first value may beprocessed quickly due to its small size [e.g., by utilizing look-uptables in the fast-relay-module in the second wireless terminal]),reduce decoding-delays (e.g., the first value may be decoded quicklyand/or accurately due to its base-rate modulation [e.g., by utilizing afast decoder that may require special conditions {e.g., works only forbase-rate modulation-schemes; requires high SINR to decode; etc.} in thefast-relay-module in the second wireless terminal]), and reducescheduling and/or routing delays (e.g., due to faster MAC-layer responsetimes [e.g., due to lower processing-delays, decoding-delays, etc.],readily available cross-layer information [e.g., scheduling information,routing information, etc.], etc.).

In some embodiments, in order to determine whether to relay, the secondwireless terminal (e.g. the fast-relay-module in the second wirelessterminal) may use one or more topological factors (e.g., signal-quality,path-loss, relative wireless direction, absolute wireless direction,etc.). The second wireless terminal (e.g., a topology-estimation-modulein the second wireless terminal) may estimate the topology of nearbywireless terminals (e.g., the first wireless terminal, the thirdwireless terminal, etc.) to facilitate determination (e.g., by thefast-relay-module in the second wireless terminal) of whether to relay(e.g. relay immediately; relay after a delay of 100 us; relay whenenable-relay-indicator is ‘1’; do not relay and terminate multi-hopwireless route; etc.). In some embodiments, topology estimation mayprovide the second wireless terminal an indication of the signal-quality(e.g., SINR of 10 dB, SINR of 20 dB, etc.) of wireless signals (e.g.,beacon-frame, data-frames, management-frames, control-frames, etc.)received from nearby wireless terminals. In some embodiments, a wirelesssignal (e.g., beacon-frame, data-frames, management-frames,control-frames, etc.) may include an indication (e.g., data indicativeof the absolute transmit power-level used by the first wireless terminalmay be included in the wireless signal by a transmit-power-module in thefirst wireless terminal) of the absolute transmit power-level (e.g., 10dBm, 20 dBm, etc.) used by a nearby wireless terminal (e.g., the firstwireless terminal) when transmitting the wireless signal. When thesecond wireless terminal receives the wireless signal, based (e.g.,ratio of the absolute transmit power-level and the signal-quality) onthe indication of the absolute transmit power-level and thesignal-quality (e.g., received-signal-strength-indication [RSSI] ,signal-to-noise-ratio [SNR], signal-to-interference-and-noise-ratio[SINR], channel-quality-indicator [CQI], etc.) with which the wirelesssignal was received at the second wireless terminal, the second wirelessterminal (e.g., the topology-estimation-module in the second wirelessterminal) may measure the path-loss (e.g., path-loss may range from 0 dBto 100 dB) or channel-loss (e.g., channel-loss may range from 0 dB to100 dB) between the transmitter (e.g. the first wireless terminal) ofthe wireless signal and the second wireless terminal. The measuredpath-loss or channel-loss estimate may then be used to facilitatedetermination (e.g., by the fast-relay-module in the second wirelessterminal) of whether to relay (e.g. relay immediately; relay after adelay of 100 us; relay when enable-relay-indicator is ‘1’; do not relayand terminate multi-hop wireless route; etc.). In some embodiments, thesecond wireless terminal may have several radio antennas. When thesecond wireless terminal receives a wireless signal (e.g., from thefirst wireless terminal), the seocnd wireless terminal (e.g., thetopology-estimation-module in the second wireless terminal) may measurethe relative wireless direction (e.g., relative direction from whichwireless signals transmitted by the first wireless terminal are receivedat the second wireless terminal with high signal-quality) of thetransmitter (e.g., the first wireless terminal) of the wireless signalbased on at least one of the following: the beam-forming weights used bythe transmitter of the wireless signal; and the received signal at eachof the radio antennas of the second wireless terminal (e.g.,corresponding to the parameters used for maximal-ratio-combining at thesecond wireless terminal when receiving the wireless signal. In someembodiments, if the absolute orientation of the radio antennas of thesecond wireless terminal is known (e.g., in a general-purpose processor[e.g., CPU] in the second wireless terminal; in the computer programproduct being executed in the second wireless terminal; in the memory ofthe second wireless terminal, etc.), the second wireless terminal (e.g.,the topology-estimation-module in the second wireless terminal) maydetermine the absolute wireless direction (e.g., by using the relativewireless direction of the first wireless terminal and the absoluteorientation of the radio antennas of the second wireless terminal) ofthe transmitter of a wireless signal (e.g., the first wireless terminal)at the second wireless terminal.

In some embodiments, the second wireless terminal (e.g., havingfull-duplex capabilities and participating in wormhole routing) mayrelay (e.g., the fast-relay-module in the second wireless terminal mayrelay) and jam (e.g., a full-duplex-jammer-module in the second wirelessterminal may jam) if wireless space is available (e.g., when the secondwireless terminal is scheduled to transmit wireless signals); otherwise,the second wireless terminal (e.g., the fast-relay-module in the secondwireless terminal) may end the wormhole (e.g., by delaying relaying by100 us; by delaying relaying till enable-relay-indicator is ‘1’; etc.)and wait to schedule at the next feasible opportunity (e.g., wait tillthe second wireless terminal is scheduled to transmit wireless signals).

In some embodiments, a device may allocate space in a data-frame (e.g.,MAC-header, IP-header, the first value, the second value, etc.) forreal-time protocol feedback (e.g. some aspects of real-time transportcontrol protocol [RTCP] feedback) from the device to facilitatemulti-hop wireless routing and scheduling. In some embodiments, theallocated space (e.g. a byte in the data-frame) may not be encrypted sothat it can be snooped by lower layers (e.g. MAC layer). In someembodiments, other cross-layer collaboration may be possible with thisextension.

In another embodiment of the present invention, a method for enhancingsocial interaction is provided. Users of mobile terminals often desireto interact socially with others (e.g., others in physical proximity),but identifying these potential interactions is difficult due to thelarge number of potential interactions. This problem may be mitigated bysome embodiments of the following method. The method, in someembodiments, includes a first wireless terminal (e.g., asocial-interaction-module in the first wireless terminal) transmitting afirst data (e.g., the first data is 1-byte in size, the first data is4-bytes in size, etc.). The method further includes a second wirelessterminal (e.g., a social-interaction-module in the second wirelessterminal) receiving the first data. In addition, the method furtherincludes the second wireless terminal (e.g., thesocial-interaction-module in the second wireless terminal) determiningwhether the first data and a second data (e.g., the second data is1-byte in size, the second data is 4-byte s in size, etc.) are a match.Furthermore, the method further includes the second wireless terminal(e.g., the social-interaction-module in the second wireless terminal)requesting communication with the first wireless terminal (e.g., thesocial-interaction-module in the first wireless terminal) if a match(i.e. between the first data and the second data) exists. Additionally,the method further includes the first wireless terminal (e.g., thesocial-interaction-module in the first wireless terminal) accepting thesecond wireless terminal's request (e.g., a request from thesocial-interaction-module in the second wireless terminal) to establishcommunication. In some embodiments, the first wireless terminal (e.g.,the social-interaction-module in the first wireless terminal) may causea change in the display (e.g. of the first wireless terminal) andpresent a user (e.g. of the first wireless terminal) with an option toselect between accepting and rejecting the second wireless terminal'srequest (e.g., the request from the social-interaction-module in thesecond wireless terminal) to establish communication.

In the above embodiment, the second wireless terminal may determinewhether the first data and the second data are a match based on at leastone of the following factors: information about the first data,user-profile corresponding to the first data, information about thesecond data, user-profile corresponding to the second data, and a seconduser-adjustable parameter. Moreover, the second wireless terminal mayrequest communication with the first wireless terminal if a match existsand if the operator of the second wireless terminal chooses to do so.Furthermore, the second wireless terminal may transmit the second datawhen requesting communication with the first wireless terminal. Also,the first wireless terminal may accept the second wireless terminal'srequest to establish communication based on at least one of thefollowing factors: information about the first data, user-profilecorresponding to the first data, information about the second data,user-profile corresponding to the second data, a first user-adjustableparameter, and choice of the operator of the first wireless terminal.

FIG. 12 is a flowchart of a method for enhancing social interaction inaccordance with an embodiment of the present invention. In step 1204, afirst wireless terminal transmits a first data. In step 1206, a secondwireless terminal receives the first data. In step 1208, the secondwireless terminal determines whether the first data and a second dataare a match. In step 1210, the second wireless terminal decides whetherthe first data and the second data match. In step 1214, the secondwireless terminal requests communication with the first wirelessterminal. In step 1216, the first wireless terminal decides whether toaccept the request from the second wireless terminal. In step 1220, thefirst wireless terminal accepts the second wireless terminal's requestto establish communication.

The above embodiment may enhance social interaction between humanbeings, other animals, intelligent machines, and other devices. In someembodiments, wireless terminals (e.g., a social-interaction-module in awireless terminal) may use occasional beaconing to send out theend-user's Person ID (PID). Wireless terminals (e.g., asocial-interaction-module in a wireless terminal), in some embodiments,may also receive PIDs by receiving beacons. In some embodiments,wireless terminals (e.g., a social-interaction-module in a wirelessterminal) may try to check whether received PIDs are a match for theuser using a local cache (e.g., in a general-purpose processor [e.g.,CPU] in a wireless terminal; in the computer program product beingexecuted in a wireless terminal; in the memory of a wireless terminal,etc.). In some embodiments, end-users may also configure level ofsocialness (e.g., in a social-interaction-module in a wireless terminalvia a user-interface [e.g., keyboard, touch-screen, etc.]) depending onnature and habits to control how many PIDs are considered a match (e.g.,by a social-interaction-module in a wireless terminal). In someembodiments, checking local cache (e.g., data is retrieved from thelocal cache by a social-interaction-module in a wireless terminal whenchecking for matches) first may be useful in some situations, such ascollege campuses, where engineers may mostly hang around each other. Insome embodiments, if received PIDs are not found (e.g., by asocial-interaction-module in a wireless terminal) in the local cache,wireless terminals may send PIDs to an Internet-based or cloud-basedserver. Server could return brief information on each of the closematches. A user may then decide whether the user wants to engage (e.g.,a social-interaction-module in a wireless terminal may present a display[e.g., screen or tactile] to the user, receive an input from the user toselect whether the user wants to engage, and act in response toreceiving the input from the user). Another user may similarly decidewhether to engage. In some embodiments, wireless traffic may beexchanged between wireless terminals (e.g., betweensocial-interaction-modules in wireless terminals) to establish thisengagement. Furthermore, in some embodiments, an indication (e.g., agreen light displayed on the screen of the wireless terminals of theusers) may show that both are interested in engaging.

In some embodiments, wireless terminals (e.g. social-interaction-modulesin wireless terminals) may use one or more topological factors (e.g.,signal-quality, path-loss, relative wireless direction, absolutewireless direction, GPS, assisted-GPS, cellular-tower-triangulation,etc.) to find approximate locations of each other and to help users(i.e. those interested in engaging) to find each other. A first wirelessterminal (e.g., a topology-estimation-module in the first wirelessterminal) may estimate the topology of nearby wireless terminals (e.g.,a second wireless terminal, a third wireless terminal, etc.) to find thelocations of nearby wireless terminals. In some embodiments, topologyestimation may provide the first wireless terminal an indication of thesignal-quality (e.g., SINR of 10 dB, SINR of 20 dB, etc.) of wirelesssignals (e.g., beacon-frame, data-frames, management-frames,control-frames, etc.) received from nearby wireless terminals. In someembodiments, a wireless signal (e.g., beacon-frame, data-frames,management-frames, control-frames, etc.) may include an indication(e.g., data indicative of the absolute transmit power-level used by asecond wireless terminal may be included in the wireless signal by thetransmit-power-module in the second wireless terminal) of the absolutetransmit power-level (e.g., 10 dB m, 20 dB m, etc.) used by a nearbywireless terminal (e.g., a second wireless terminal) when transmittingthe wireless signal. When the first wireless terminal receives thewireless signal, based (e.g., ratio of the absolute transmit power-leveland the signal-quality) on the indication of the absolute transmitpower-level and the signal-quality (e.g.,received-signal-strength-indication [RSSI] , signal-to-noise-ratio[SNR], signal-to-interference-and-noise-ratio [SINR],channel-quality-indicator [CQI], etc.) with which the wireless signalwas received at the first wireless terminal, the first wireless terminal(e.g., a topology-estimation-module in the first wireless terminal) maymeasure the path-loss (e.g., path-loss may range from 0 dB to 100 dB) orchannel-loss (e.g., channel-loss may range from 0 dB to 100 dB) betweenthe transmitter of the wireless signal and the first wireless terminal.The measured path-loss or channel-loss estimate may then be used insteadof the signal-quality to select multi-hop routes. In some embodiments,the first wireless terminal may have several radio antennas. When thefirst wireless terminal receives a wireless signal (e.g., from a secondwireless terminal), the first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may measurethe relative wireless direction (e.g., relative direction from whichwireless signals transmitted by a second wireless terminal are receivedat the first wireless terminal with high signal-quality) of thetransmitter (e.g., a second wireless terminal) of the wireless signalbased on at least one of the following: the beam-forming weights used bythe transmitter of the wireless signal; and the received signal at eachof the radio antennas of the first wireless terminal (e.g.,corresponding to the parameters used for maximal-ratio-combining at thefirst wireless terminal when receiving the wireless signal. In someembodiments, if the absolute orientation of the radio antennas of thefirst wireless terminal is known (e.g., in a general-purpose processor[e.g., CPU] in the first wireless terminal; in the computer programproduct being executed in the first wireless terminal; in the memory ofthe first wireless terminal, etc.), the first wireless terminal (e.g., atopology-estimation-module in the first wireless terminal) may determinethe absolute wireless direction (e.g., by using the relative wirelessdirection of a second wireless terminal and the absolute orientation ofthe radio antennas of the first wireless terminal) of the transmitter ofa wireless signal (e.g., a second wireless terminal) at the firstwireless terminal.

In some embodiments, if a first user tries to engage without getting anindication (e.g., a green light is not displayed on the screen of thewireless terminal of the first user) and gets rejected by a second user(e.g. when the first user approaches the second user), the first user'swireless terminal (e.g., a social-interaction-module in the first user'swireless terminal) could ban people (or PID) updates on the first user'swireless terminal for some amount of time. In some embodiments, wirelessterminals (e.g., a social-interaction-module in the first user'swireless terminal; a social-interaction-module in the second user'swireless terminal; etc.) may be able to detect whether they haveapproached (e.g., a topology-estimation-module in the first user'swireless terminal may first sense gradually increasing proximity to thesecond user's wireless terminal; next, the topology-estimation-module inthe first user's wireless terminal may sense that the second user'swireless terminal is stationary for some period of time [e.g., 1-second,10-seconds, etc.]; in this way, the topology-estimation-module in thefirst user's wireless terminal may enable it to detect the action ofapproaching the second user's wireless terminal) each other in recenttimes (e.g., 30-seconds, 60-seconds, etc.). In some embodiments,however, occasional beaconing (e.g., with the PID in the beacon-frames)could still happen on the first user's wireless terminal, and if a thirduser wants to meet the first user, the first user's wireless terminal(e.g., the social-interaction-module in the first user's wirelessterminal) may allow that. In some embodiments, offender (e.g. the firstuser) initiated approaches may not be allowed (at least aided byoffender's wireless terminal) till ban time has elapsed.

Some embodiments of the above invention may distract end-users in someenvironments. Thus, in some embodiments, a wireless terminal may (e.g.after obtaining mobility data [e.g., by interrogating accelerometer,GPS, etc.]) disable (e.g., set a register or variable that gates socialinteraction in the social-interaction-module in the first wirelessterminal) most such social interaction functionality when vehicularmotion (e.g. vehicular motion at 60 km/hr) is detected (e.g. end-usercould potentially be driving the vehicle while using the wirelessterminal for social functionality). Special wireless terminals (such asthose installed in a bus/train) fixed inside trains and buses may appearstationary to other wireless terminals being used by people. Presence(e.g., detected by a topology-estimation-module in a user's wirelessterminal) of such relatively stationary wireless terminals may be usedto detect motion of buses and trains. Social interaction functionalitymay be enabled in such situations for passengers when relativelystationary wireless terminals (e.g. the type installed in a bus/train)are detected using features of the above embodiment. Using features ofthe above embodiment, transport companies could block social interactionfunctionality for devices owned by drivers of trains and buses tomitigate distractions.

In another embodiment of the present invention, a method for improvingthe performance of a wireless network is provided. Overhead in networkshaving a shared medium and no centralized control can be a problem, andrelatively large amounts of bandwidth can be consumed coordinatingoperation of the network participants. This problem is particularlyacute in multi-hop networks, as the number of participants may be largerelative to single-hop networks. FIG. 13 illustrates a method that, insome applications, reduces overhead. The method, in some embodiments,includes a first wireless terminal (e.g., a frame-reconstruction-modulein the first wireless terminal) transmitting a first data (e.g.1000-bytes in size, 1500-bytes in size). The method further includes asecond wireless terminal receiving the first data. In addition, themethod further includes the second wireless terminal transmitting asecond data (e.g. MAC-layer ACK-frame). Furthermore, the method furtherincludes the first wireless terminal (e.g., theframe-reconstruction-module in the first wireless terminal) receivingthe second data. Additionally, the method further includes the firstwireless terminal (e.g., the frame-reconstruction-module in the firstwireless terminal) constructing a third data (e.g. TCP-layer ACK-frame)based on at least one of the following: the first data and the seconddata. Moreover, the method further includes the first wireless terminal(e.g., the frame-reconstruction-module in the first wireless terminal)transmitting the third data to the original source of the first data(e.g. the original source of the first data may be the first wirelessterminal; the original source of the first data may be a serverconnected to the Internet that is reachable via the first wirelessterminal; etc.). Moreover, the second data may be amedium-access-control (MAC) acknowledgement (ACK). Furthermore, thethird data may be a transmission-control-protocol (TCP) acknowledgement(ACK).

FIG. 13 is a flowchart of a method for improving the performance of awireless network in accordance with an embodiment of the presentinvention. In step 1304, a first wireless terminal transmits a firstdata. In step 1306, a second wireless terminal receives the first data.In step 1308, the second wireless terminal transmits a second data. Instep 1310, the first wireless terminal receives the second data. In step1312, the first wireless terminal constructs a third data based on atleast one of the following: the first data and the second data. In step1314, the first wireless terminal transmits the third data to theoriginal source of the first data.

The above invention, in some embodiments, is expected to allowintelligent reconstruction of responses and reduce consumption ofwireless network resources. It is expected to facilitatemedium-access-control (MAC) acknowledgement (ACK) aidedtransmission-control-protocol (TCP) acknowledgment (ACK) reconstruction.This may help reduce network congestion, improve spectral efficiency,and increase total network throughput, though other applications arealso envisioned. For example, a first wireless terminal (e.g., theframe-reconstruction-module in the first wireless terminal) may snoop(e.g., snooped frame-reconstruction-helper-values may be obtained by theframe-reconstruction-module in the first wireless terminal from anetwork-interface-card buffer; snoopedframe-reconstruction-helper-values may then be stored by theframe-reconstruction-module in the first wireless terminal in an arrayin memory; etc.) frame-reconstruction-helper-values (e.g., a firstIP-source-address; a first IP-destination-address; a firstIP-total-length; a first TCP-source-port; a first TCP-destination-port;a first TCP-sequence-number; etc.) from the IP and TCP headers of an(encapsulated) TCP segment (e.g., the first wireless terminal obtainsthe TCP segment from an originator of the TCP segment [e.g. theoriginator of the TCP segment may be the first wireless terminal; theoriginator of the TCP segment may be a server connected to the Internetthat is reachable via the first wireless terminal; etc.]; theencapsulated TCP segment is destined for a second wireless terminal;etc.) before wirelessly sending the TCP segment to the second wirelessterminal. The first wireless terminal (e.g., theframe-reconstruction-module in the first wireless terminal) may thenobtain the snooped frame-reconstruction-helper-values (e.g., snoopedframe-reconstruction-helper-values may be stored by theframe-reconstruction-module in the first wireless terminal in an arrayin memory; snooped frame-reconstruction-helper-values may then beobtained by the frame-reconstruction-module in the first wirelessterminal from the array in memory; etc.) and use the snoopedframe-reconstruction-helper-values to reconstruct the corresponding(e.g., the (encapsulated) TCP ACK that the second wireless terminal mayhave sent back [in some embodiments] to the first wireless terminal) TCPACK (e.g., by using the first IP-source-address as theIP-destination-address in the IP-header of the corresponding TCP ACK; byusing the first IP-destination-address as the IP-source-address in theIP-header of the corresponding TCP ACK; by using the firstTCP-source-port as the TCP-destination-port in the TCP-header of thecorresponding TCP ACK; by using the first TCP-destination-port as theTCP-source-port in the TCP-header of the corresponding TCP ACK; etc.).In some embodiments, if the first wireless terminal receives the MAC ACKfor the (encapsulated) TCP segment from the second wireless terminal,the first wireless terminal (e.g., the frame-reconstruction-module inthe first wireless terminal) may send the reconstructed TCP ACK to theoriginator of the TCP segment (e.g. the originator of the TCP segmentmay be the first wireless terminal; the originator of the TCP segmentmay be a server connected to the Internet that is reachable via thefirst wireless terminal; etc.). Moreover, the second wireless terminal(e.g., a frame-suppression-module in the second wireless terminal) mayrefrain from sending the TCP ACK because of (in response to) the TCP ACKreconstruction service provided by the first wireless device. Thisrefraining (e.g., by the frame-suppression-module in the second wirelessterminal) may save network bandwidth and improve total networkthroughput because the TCP ACK does not need to be transmitted over thewireless spectrum. The gains are expected to become bigger in amulti-hop wireless network setting wherein there are other intermediaterelay wireless terminals between the first wireless terminal and thesecond wireless terminal. In such a multi-hop setting, TCP ACKreconstruction may save transmission of TCP ACKs at each of the relaywireless terminals as well. The first wireless terminal may also requestthe original source of the first data for assistance (e.g. requestoriginal source of the first data to place pertinent IP and TCPinformation in an unencrypted location within the frame containing thefirst data; etc.). This may be useful, in some systems, for TCP ACKreconstruction and calculation of checksums. In particular, it could beuseful in cellular networks because TCP and IP headers may often beencrypted along with the rest of the data payload using SIM cards andother secure keys. Moreover, it could be useful for IPsec tunneling andother protocols that encrypt the TCP and IP headers and affect TCP ACKreconstruction by intermediate nodes.

In another embodiment of the present invention, H-antennas may use themagnetic portion of the electromagnetic waves to modulate and demodulateinformation (e.g., bits of data, bytes of data, etc.) ontowireless-signals. In some embodiments, H-antennas may often see pathloss exponents of 6 or more and this may be useful for multi-hopwireless networks (e.g., to facilitate aggressive spatial reuse). Insome embodiments, H-antennas may be surface-mounted on walls ofbuildings using several mechanisms (e.g., mixing several small-sizeH-antennas with wall-paint and then applying a coat of the wall-paint ona wall). In some embodiments, H-antennas may be non-uniformly applied onwalls of buildings (e.g., resulting in multi-hop wireless routes ofvarying reliability) and may increase reliability (e.g., of multi-hopwireless routes) by applying special techniques (e.g., crowdsourcing,network-coding, etc.). In some embodiments, H-antennas may consist ofspecial materials (e.g., ferroelectric materials, pyroelectricmaterials, etc.) to facilitate operation in civilian settings (e.g., ona wall of a building).

In another embodiment of the present invention, a method for improvingthe performance of a wireless network is provided. The method, in someembodiments, includes a first wireless terminal transmitting a firstdata. In addition, the method further includes a second wirelessterminal transmitting a second data at a first power level while (e.g.,simultaneously) receiving the first data. Furthermore, the methodfurther includes the second wireless terminal mitigating the effects oftransmitting the second data to decode the first data.

In the above embodiment, the second wireless terminal may transmit thesecond data at the first power level while receiving the first databased on at least one of the following: the second data is predetermined(e.g., predetermined to the second wireless device); the second datadepends on the first data (e.g., on the physical-layer rate of the firstdata; on the signal-to-interference-and-noise-ratio when receiving thefirst data at the second wireless device); the first power level ispredetermined (e.g., predetermined to the second wireless device); thefirst power level is based on one or moresignal-to-interference-and-noise-ratios (e.g., on thesignal-to-interference-and-noise-ratio when receiving the first data atthe second wireless device); and the first power level is based on thephysical-layer rate (e.g., modulation scheme, coding scheme, number ofspatial streams, bandwidth of spectrum used, etc.) of the first data.

In the above embodiment, the second wireless terminal may mitigate theeffects of transmitting the second data to decode the first data basedon at least one of the following: the second wireless terminal alsotransmits a third data that may be dependent on the first data (e.g., onthe analog waveform corresponding to the first data; on the digitalsamples corresponding to the first data; etc.) and/or the second data(e.g., on the analog waveform corresponding to the second data; on thedigital samples corresponding to the second data; etc.); the secondwireless terminal mathematically removes (e.g., by subtracting thedigital samples corresponding to the second data from the digitalsamples corresponding to the sum of the first data and the second data)the effects of transmitting the second data to decode the first data;and the second wireless terminal algorithmically removes (e.g., byapplying a filter that exploits the structure of the predeterminedsecond data to isolate the first data from the second data) the effectsof transmitting the second data to decode the first data.

In the above embodiment, the second data may indicate (e.g., explicitlyindicate via the contents of the second data; implicitly indicate viathe physical-layer rate of the second data; implicitly indicate via thepower-level of the second data; etc.) at least one of the following tothe first wireless terminal: the signal-to-interference-and-noise-ratioat the second wireless terminal (e.g., when receiving the first data);information about the first data (e.g., thesignal-to-interference-and-noise-ratio when receiving the first data atthe second wireless terminal); and information about the decoding of thefirst data (e.g., decoding of the first data 100% successful; decodingof the first data 50% successful; decoding of a first fragment of thefirst data successful; decoding of a second fragment of the first dataunsuccessful; etc.) at the second wireless terminal.

In the above embodiment, the second data may indicate (e.g., explicitlyindicate via the contents of the second data; implicitly indicate viathe physical-layer rate of the second data; implicitly indicate via thepower-level of the second data; etc.) at least one of the following to athird wireless terminal: the signal-to-interference-and-noise-ratio atthe second wireless terminal (e.g., when receiving the first data);information about the first data (e.g., thesignal-to-interference-and-noise-ratio when receiving the first data atthe second wireless terminal); and information about the decoding of thefirst data (e.g., decoding of the first data 100% successful; decodingof the first data 50% successful; decoding of a first fragment of thefirst data successful; decoding of a second fragment of the first dataunsuccessful; etc.) at the second wireless terminal.

FIG. 14 is a flowchart of a method for improving the performance of awireless network in accordance with an embodiment of the presentinvention. In step 1404, in this embodiment, a first wireless terminaltransmits a first data. In step 1406, a second wireless terminaltransmits a second data at a first power level while receiving the firstdata, based on least one of the following: the second data ispredetermined (e.g., predetermined to the second wireless device); thesecond data depends on the first data (e.g., on the physical-layer rateof the first data; on the signal-to-interference-and-noise-ratio whenreceiving the first data at the second wireless device); the first powerlevel is predetermined (e.g., predetermined to the second wirelessdevice); the first power level is based on one or moresignal-to-interference-and-noise-ratios (e.g., on thesignal-to-interference-and-noise-ratio when receiving the first data atthe second wireless device); and the first power level is based on thephysical-layer rate (e.g., modulation scheme, coding scheme, number ofspatial streams, bandwidth of spectrum used, etc.) of the first data. Instep 1408, the second wireless terminal mitigates the effects oftransmitting the second data to decode the first data, based on at leastone of the following: the second wireless terminal also transmits athird data that may be dependent on the first data (e.g., on the analogwaveform corresponding to the first data; on the digital samplescorresponding to the first data; etc.) and/or the second data (e.g., onthe analog waveform corresponding to the second data; on the digitalsamples corresponding to the second data; etc.); the second wirelessterminal mathematically removes (e.g., by subtracting the digitalsamples corresponding to the second data from the digital samplescorresponding to the sum of the first data and the second data) theeffects of transmitting the second data to decode the first data; andthe second wireless terminal algorithmically removes (e.g., by applyinga filter that exploits the structure of the predetermined second data toisolate the first data from the second data) the effects of transmittingthe second data to decode the first data.

In one example scenario, a transmitter is transmitting frames to areceiver. In this example, the above embodiment may be used by thereceiver to transmit a protection signal as soon as it starts receivingan RTS-like frame or data frame from the transmitter. Such a protectionsignal (e.g., a frame encoding a command to other devices to stoptransmitting; a wireless signal encoding a command to other devices tostop transmitting; etc.) may prevent other nodes in the vicinity of thereceiver from transmitting and causing interference for the receiver. Apre-calculated signal may be used and may readily be subtracted fromwhat is received from the desired transmitter. Signal strength ofprotection signal may be selected (e.g., by aprotection-signal-generator-module in a wireless device) based onabsolute transmit power levels of beacons, received power of beaconsfrom the transmitter and other nodes, topology of nearby nodes,physical-layer rate being used by the transmitter, estimated SINR at thereceiver, signal strength and quality at which RTS and/or data framesare received from the transmitter, and estimates of path-losses tonearby nodes and the transmitter. Physical-layer rates are selectedbased on combinations of antenna configurations, spectrum allocations,spatial streams, modulations, and coding schemes. The receiver may use adifferent IFS value to transmit wireless communication signaling tonearby nodes to indicate the physical-layer rate being used by thetransmitter (and thus the rate that the receiver will have to decode).Potential interferers may respond by determining whether to transmit(and interfere with the receiver) based on the protection signal andother wireless communication signaling. This could be considered as anintelligent way to do carrier sensing. Instead of having on-offscheduling, in some embodiments, wireless nodes may makemulti-dimensional decisions based on several factors, such as topology,activity, schedules, needs, traffic patterns, and physical-layer ratesbeing used by other wireless nodes.

Although the method, wireless device and computer program product aredescribed in connection with several embodiments, it is not intended tobe limited to the specific forms set forth herein, but on the contrary,it is intended to cover such alternatives, modifications andequivalents, as can be reasonably included within the spirit and scopeof the invention as defined by the appended claims.

The invention claimed is:
 1. A method of coordinating use of a wirelessmedium among wireless devices that are out of range of one another, themethod comprising: receiving, by a first wireless device operating as anode of a hybrid cellular and non-cellular multi-hop wireless network, afirst request-to-send (RTS) signal transmitted from a second wirelessdevice to a third wireless device, the RTS signal being wirelesslytransmitted by the second wireless device in response to data in anoutput buffer of the second wireless device destined for the thirdwireless device; receiving, by the first wireless device, a second RTSsignal transmitted from a fourth wireless device to the first wirelessdevice, the second RTS signal being wirelessly transmitted by the fourthwireless device in response to data in an output buffer of the fourthwireless device destined for the first wireless device, the fourthwireless device being out of range of the second wireless device; inresponse to the first RTS signal, determining, by the first wirelessdevice, to delay a transmission of a first clear-to-send (CTS) signalfrom the first wireless device until an acknowledgement (ACK) signal istransmitted from the third wireless device to the second wirelessdevice; receiving the ACK signal, by the first wireless device, the ACKsignal being wirelessly transmitted from the third wireless device tothe second wireless device in response to receipt of data by the thirdwireless device from the second wireless device; and in response to theACK signal, wirelessly transmitting a second CTS signal from the firstwireless device to the fourth wireless device.
 2. The method of claim 1,comprising receiving data frames, by the first wireless device, from thefourth wireless device after transmitting the second CTS signal.
 3. Themethod of claim 1, wherein the first wireless device is a cell phone. 4.The method of claim 1, wherein receiving the ACK signal comprisesreceiving the ACK signal via a non-cellular interface of the firstwireless device.
 5. A method of routing data in a multi-hop wirelessnetwork, the method comprising: obtaining, by a first wireless device,data indicative of whether signal-quality of transmissions from a secondwireless device to the first wireless device are above a firstthreshold, wherein the first threshold is greater than or equal toapproximately 0 decibels; obtaining, by the first wireless device, dataindicative of whether signal-quality of transmissions from a thirdwireless device to the first wireless device are above a secondthreshold, wherein the second threshold is greater than or equal toapproximately 30 decibels; based on the obtained data, by the firstwireless device, determining to route data from the first wirelessdevice to the second wireless device through the third wireless device;and in response to the determination, transmitting data to the thirdwireless device for relay to the second wireless device.
 6. The methodof claim 5, wherein the data indicative of whether signal-quality oftransmissions from the second wireless device to the first wirelessdevice are above the first threshold comprises a beacon frametransmitted by the second wireless device.
 7. The method of claim 5,wherein the data indicative of whether signal-quality of transmissionsfrom the second wireless device to the first wireless device are abovethe first threshold indicates signal-quality above the first thresholdand less than the second threshold.
 8. The method of claim 5, whereinthe data indicative of whether signal-quality of transmissions from thesecond wireless device to the first wireless device are above the firstthreshold indicates low signal-quality above the first threshold andless than the second threshold.
 9. The method of claim 8, wherein thelow signal-quality is less than 20 decibels.
 10. The method of claim 8,wherein the second threshold is indicative of a high signal-quality. 11.The method of claim 5, wherein determining to route data from the firstwireless device to the second wireless device through the third wirelessdevice based on the obtained data comprises: determining thesignal-quality of transmissions from the second wireless device to thefirst wireless device are above the first threshold and less than thesecond threshold; and determining the signal-quality of transmissionsfrom the third wireless device to the first wireless device are abovethe second threshold.
 12. The method of claim 11, wherein: thesignal-quality of transmissions above the first threshold and less thanthe second threshold are of lower quality, and the signal-quality oftransmissions above the second threshold are of high quality.
 13. Themethod of claim 5, wherein determining to route data from the firstwireless device to the second wireless device through the third wirelessdevice based on the obtained data comprises: determining thesignal-quality of transmissions from the second wireless device to thefirst wireless device are less than 20 decibels; and determining thesignal-quality of transmissions from the third wireless device to thefirst wireless device are greater than 30 decibels.
 14. A method ofrelaying data in a multi-hop network, the method comprising: receiving,by a first wireless device, a data frame and a first value bothwirelessly transmitted from a second wireless device, the first valuehaving a size smaller than or approximately equal to 4 bytes;determining, by the first wireless device, to relay the data frame basedon the first value; in response to the determination, selecting, by thefirst wireless device, a third wireless device to receive the dataframe; and in response to the determination, transmitting, by the firstwireless device, the data frame and a second value calculated by thefirst wireless device to the third wireless device.
 15. The method ofclaim 14, wherein the first value is based on a medium-access control(MAC) address of the second wireless device.
 16. The method of claim 14,wherein the first value is based on a destination MAC address.
 17. Themethod of claim 14, wherein the data frame comprises the first value.18. A method of reconstructing an acknowledgement signal, the methodcomprising: wirelessly receiving, by a first wireless device operatingas a node of a hybrid cellular and non-cellular multi-hop network, dataframes from a second device to be relayed to a third wireless device;snooping, by the first wireless device,frame-reconstruction-helper-values from header information of the dataframes; wirelessly transmitting, by the first wireless device, the dataframes to the third wireless device along with a signal commanding thethird wireless device to not transmit an acknowledgement signal for thesecond device; constructing, by the first wireless device, based onframe-reconstruction-helper-values, an acknowledgement signal; andtransmitting the acknowledgement signal to the second device.
 19. Themethod of claim 18, wherein the frame-reconstruction-helper-values arebased on internet protocol and transmission control protocol (TCP)headers of an encapsulated TCP segment.